Article

Effectiveness of California’s High Occupancy Vehicle (HOV) system

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Abstract

The effectiveness of California’s 1171 mile High Occupancy Vehicle (HOV) system is assessed using peak hour traffic data from 700+ loop detector stations over many months. The study reaches the following conclusions.(1) HOV lanes are under-utilized: 81% of HOV detectors measure flows below 1400 vehicles per hour per lane (vphpl) during the PM peak hour. (2) Many HOV lanes experience degraded operations: 18% of all HOV miles during the AM peak hour and 32% during the PM peak hour have speeds below 45 mph for more than 10% of weekdays. (3) HOV lanes suffer a 20% capacity penalty, achieving a maximum flow of 1600 vphpl at 45 mph vs. maximum flow above 2000 vphpl at 60 mph in general purpose (GP) lanes. (4) HOV lanes offer small travel time savings. The mean savings over a random 10-mile route on an HOV lane vs. the adjacent GP lane is 1.7 min and the median is 0.7 min; however, HOV travel times are more reliable. (5) Travel time savings do not provide a statistically significant carpooling incentive. (6) A system with one HOV lane and three GP lanes carries the same number of persons per hour as a system with four GP lanes. (7) HOV lanes reduce overall congestion slightly only when the general purpose lanes are allowed to become congested.Despite these findings, HOV facilities can play a useful role in a well-managed freeway system in California. In particular, they can be useful if there is a significant number of buses or vanpools; as a 2-lane HOV/HOT facility, which eliminates capacity loss; and, with efficient metering, as a HOV/HOT bypass at the on-ramps.

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... However, in some cases, the HOV lanes are underutilized when the whole 4 freeway system is congested. In (1), for more than 700 detector stations in California during PM 5 peak hours of 128 weekdays in 2005, the flow-rates of 81% HOV lanes were below 1400 vphpl, 6 and most of them had speeds over 45 mph and thus are underutilized. 7 High-occupancy toll (HOT) lanes, which combine HOV lanes and congestion pricing strate-8 gies by charging single-occupancy vehicles (SOVs) to use HOV lanes during peak periods, have in California, Florida and Texas. ...
... They assumed that the traffic flow switching to the HOT lane had no impact on the traffic condition of general purpose (GP) lanes. However, 1 traffic conditions on different lane groups were proved to be important in setting the tolls. In (10), 2 they assumed that the demand of the HOT lane could never be higher than the capacity, and then 3 provided dynamic pricing strategies to achieve different objectives, including minimizing delay 4 and maximizing revenue. ...
... We also assume the arrival flow-rate of HOVs is below the HOT lane's capacity, i.e., q 1 (t) < C 1 . 1 In this case, some SOVs can pay to use the HOT lane. The flow-rates downstream on GP and HOT 2 lanes should be q 2 (t) − q 3 (t) and q 1 (t) + q 3 (t), respectively. ...
Conference Paper
High-occupancy toll (HOT) lanes are managed lanes that combines high-occupancy vehicle (HOV) lanes with congestion pricing strategies. Some possible objectives of operating HOT lanes include: (i) maintaining a certain Level-of-service (LOS) on HOT lanes; (ii) improving overall system performance; (iii) maximizing revenue for private sectors. Some agencies claimed that revenue maximization should generally coincide with the optimization of freeway performances. But this statement has not been carefully examined. In this study, we will use the optimal control theory to formulate and solve the revenue maximization problem when the freeway is congested. A point queue model (PQM) for traffic and a multinomial logit model (MNL) for lane group choice are two constraints for the problem. We will first provide the optimality conditions and then provide an iterative method to solve the control problem. We also present numerical examples to show how the method works. We compare the revenue and system performance with our previous study in the same simulation setups. The conclusions are as follows: if the total demand is slightly higher than capacity and the demand of HOVs is low, operators can maximize revenue and keep free-flow speed on the HOT lane at the same time; if the demand of HOVs is high, operators can design a pricing scheme that maximizes revenue while minimizing total travel delay.
... In contrast, high occupancy vehicle (HOV) lane provides a more reliable expressway (Yang, 1998). But still, these lanes are accused of low utility level, and purely loosening the criteria of vehicle occupancy cannot solve this problem (Kwon and Varaiya, 2008;Brown and Aicp, 2008).To this end, HOT lane is proposed to allow LOVs when they pay a specified fare (Jang et al., 2014), which has been recently explored regarding design, simulation, implementation, and evaluation (Lombardi et al., 2021). Empirical research has pointed that travelers use HOT lanes on an infrequent basis (Burris and Stockton, 2004), and the scientific fare rate is critical to HOT lane success. ...
... Thus it is concluded that intense trip demand corresponds to higher HOV occupancy and LOV price rate, i.e., stricter MFEL management criteria, to balance the demand on MFEL and GPL as given by the saturation rate in Fig. 5. Such finding extends the empirical research concluding that HOV critical occupancy itself cannot enhance road utility (Brown and Aicp, 2008;Kwon and Varaiya, 2008), providing insights to the optimal combination of HOV occupancy and LOV price rate. Figure 7 demonstrates that the proposed MFEL management scheme reduces total traffic delay whatever passenger demand level is, consistent to the finding in previous research (Yang, 1998;Tan and Gao, 2018) but to a greater degree. ...
Article
Priority to emergency vehicles, buses, high occupancy vehicles (HOVs), and priced low occupancy vehicles (LOVs) is critical to their efficiency and reliability, where multi-functional exclusive lane (MFEL) serves as a salient element with independent operation environment. To enhance MFEL utility and balance the demand between prioritized and non-prioritized vehicles, this research proposes an optimization model for MFEL design and management to comprehensively serve the trip modes with various priority levels and distinct operation patterns, considering the delay from lane access, bus stop dwelling, signalized intersections, and ride-sharing. Case study follows to calibrate and validate the proposed model under varying passenger demand and emergency vehicle frequency, finding that MFEL may reduce total travel time in all scenarios especially under high traffic demand. Sensitivity analyses test the effect of road lane count and bus occupancy on MFEL design and management, where the road with more lanes is more flexible to accommodate increased passenger demand without increasing HOV critical occupancy or LOV price rate. Moreover, higher bus occupancy assists in avoiding significant increase of LOV price rate to promote trip equity. This research may lay foundation to MFEL implementation to mitigate traffic congestion and promote transport sustainability.
... Carpool lanes are common fixtures on congested urban freeways throughout North America; e.g. see Southworth and Westbrook (1985), Newman et al. (1988), Quiroga (2000), Kwon and Varaiya (2008), Burris et al. (2009), and Qian and Zhang (2011). The lanes are used in Europe and Asia as well, though to lesser extents; e.g. ...
... System-wide improvements were thus often achieved without harming carpools. All data points presented below are averages of 10 separate simulations, with average onboard person occupancies of 1.1 for an LOV (Kwon and Varaiya, 2008), and 2.6 for a carpool (Systems Metrics Group, 2012). ...
Article
Carpool lanes that are not filled to capacity can spell trouble, particularly when deployed on narrow freeways with only 3 lanes in each travel direction. Two alternative treatments for underused carpool lanes were evaluated with this in mind. Both can boost discharge flows by opening a portion of the carpool lane to all freeway traffic in the vicinity of a bottleneck. The simpler of the two alternatives opens the lane segment on a permanent basis. The other does so intermittently. Both alternatives leave the carpool lane intact on segments well upstream of an active bottleneck. Carpools are thus still enabled to bypass slower-moving queues in a freeway’s regular-use lanes. Both alternatives have previously been proposed, but were yet to be tested. The present tests entail simulations of a real 3-lane freeway. The simulation model was calibrated to roughly match unfavorable conditions presently triggered by the site’s underused carpool lane. Experiments were thereafter performed by varying travel demands parametrically. These tests unveiled why the alternatives are likely to be better options than rescinding the site’s carpool restriction and opening the full length of the lane to all traffic. Simulations also show that, unless the carpool lane is nearly filled to capacity, the alternatives perform better than does the traditional practice of running the lane through a bottleneck. The simpler of the two alternatives performed well when the carpool lane operated at less than two-thirds its capacity. The intermittent treatment was found superior when carpool demands were higher. The savings in Vehicle Hours Traveled (VHT) and People Hours Traveled (PHT) generated by the alternatives were often large. Deploying the simpler alternative under the site’s present-day conditions, for example, was found to reduce PHT and VHT by more than 1,000 (hours) each, over a 5-h period spanning the afternoon rush. These improvements did not come at great cost to carpools. To the contrary, carpools often benefited from the alternative treatments, despite having at times to traverse the site’s bottleneck sans priority. This is because by diminishing regular-lane queues, the alternatives also diminished the deleterious friction effect on carpool-lane speeds. Policy implications for carpool- and other kinds of special-use lanes are discussed.
... However, some HOV lanes could be underutilized, even when the corresponding general purpose (GP) lanes on the same roads are congested. For example, for more than 700 detector stations in California during PM peak hours on 128 weekdays in 2005, the flow-rates of 81% HOV lanes were below 1400 vphpl, and most of them had speeds over 45 mph and thus were uncongested and underutilized [4]. ...
... Control signal With the definition of ζ(t) in (2), the feedback-based estimator in (19) and the dynamic price in (20), the point queue models in (4) and the lane choice model in (11) form a closed-loop control system. There are six unknown variables in the system: λ 1 (t), λ 2 (t), ζ(t), w(t), π(t) and u(t). ...
Article
The dynamic pricing problem of a freeway corridor with high-occupancy toll (HOT) lanes was formulated and solved based on a point queue abstraction of the traffic system [1]. However, existing pricing strategies cannot guarantee that the closed-loop system converges to the optimal state, in which the HOT lanes' capacity is fully utilized but there is no queue on the HOT lanes, and a well-behaved estimation and control method is quite challenging and still elusive. This paper attempts to fill the gap by making three fundamental contributions: (i) to present a simpler formulation of the point queue model based on the new concept of residual capacity, (ii) to propose a simple feedback control theoretic approach to estimate the average value of time and calculate the dynamic price, and (iii) to analytically and numerically prove that the closed-loop system is stable and guaranteed to converge to the optimal state, in either Gaussian or exponential manners.
... However, in some cases, HOV lanes could be underutilized, even when the parallel GP lanes on the same freeway are congested. Kwon and Varaiya (2008) investigated data from more than 700 detector stations in California during PM peak hours on 128 weekdays in 2005, and found that the flow-rates of 81% HOV lanes were below 1400 vphpl, and most of them had speeds over 45 mph and thus were uncongested and underutilized. were under construction (Perez et al., 2012); as of January 2019, 41 HOT lanes had been operated nationwide (TRB Managed Lanes Committee, 2019). ...
... Those assumptions are consistent with the findings in (Kwon and Varaiya, 2008). By introducing the HOT lanes, however, we can charge some SOVs to use the underutilized HOV lanes. ...
Thesis
The purpose of this study is to propose control theoretic approaches for high-occupancy toll (HOT) lanes operation. This dissertation considers different operation objectives, and provides pricing schemes for HOT lanes accordingly. To improve the system performance, the study �first proposes a simultaneous estimation and control method for the same system as that in (Yin and Lou, 2009). An integral controller is applied to estimate the average value of time (VOT) of SOVs, and the dynamic prices are calculated based on the logit model. The closed-loop system is proved to be stable and guaranteed to converge to the optimal state both analytically and numerically. Two convergence patterns, Gaussian or exponential, are revealed. The effect of the scale parameter in the logit model is also examined. Then, a new lane choice model, i.e., the vehicle-based user equilibrium principle, is proposed to capture the lane choice of SOVs. A general lane choice model is derived based on the characteristics of the logit and the vehicle-based UE model. An insight regarding the dynamic price is obtained by analytically solving the optimal dynamic prices with constant demands of HOVs and SOVs, and then a feedback controller is designed to determine the dynamic prices without knowing SOVs' lane choice models, but to satisfy the two control objectives: maximizing the flow-rate but not forming a queue on the HOT lanes. If the type of the lane choice model is given, the distribution of VOTs of the SOVs can be estimated. Next, an optimal control problem is proposed to examine the statement that revenue maximization should generally coincide with the optimization of freeway performances, such as maximizing overall travel-time savings or throughput. Results show that operators need to make different strategies based on the traffic demand. In order to maximize the revenue, operators should set a higher price to make the HOT lanes underutilized if the demand of HOVs is low. However, if the demand of HOVs is high, operators need to set a lower price to attract more SOVs to create congestion on the HOT lanes. It has long been known that drivers' departure time choice behavior is one fundamental cause of congestion. In the last part of this dissertation, pricing schemes are proposed to consider both lane choice and departure time choice. In the study period, the demands for the HOT and GP lanes are higher than their capacities, which means the whole freeway is congested. However, the congestion period on the HOT lanes is short than that on the GP lanes. So, the HOT lanes are "underutilized". It turns out that flat (instead of dynamic) pricing schemes are able to meet the following two constraints: (1) the total travel time and scheduling cost is minimized; and (2) the costs for each non-switching and switching SOV are the same. We show that different revenue and tolling constrains for certain type of vehicles lead to different pricing schemes.
... For instance, there are P+P lots implemented near interchanges: Germany (Parken-und-Mitfahren), the UK, the USA, Canada. the Netherlands (Figure 1a A survey in the USA [7] showed that 1% of private vehicles joining carpooling can save three billion liters of gasoline and 10% can save 28 billion liters annually. Seyedabrishami [8] claimed that about 240 million liters of fuel would be saved annually if 30% of travelers joined carpooling in Tehran. ...
... Kwon [7] discovered that some high occupancy vehicle (HOV) lanes are under-utilized in California. About 81% of HOV lanes carry below 1400 vehicles per hour per lane during peak hours. ...
Article
Full-text available
Dispersed settlement areas (e.g., Slovenia) result in lower development of fixed public transport lines and thereby car-dependent lifestyles. To avoid congestion inside the cities and on highways in these areas, shared mobility modes e.g., carpooling, is one of the effective solutions, increasing the occupancy of personal vehicles. However, passenger pickup and drop-off locations still remain an important challenge for carpool users and transport officials. As a collection point for carpooling, we can consider "park and pool (P+P)" lots near highways' interchanges. This study aims to examine the impacts of P+P lots near interchanges on carpooling behavior of users and on improving sustainable mobility on highways in such dispersed settlement areas. To do so, we employed a field survey, incorporated the P+P lots into the mode choice model, and examined different scenarios using the macroscopic transport model. It is found that factors such as travel cost, public transport service limitations, and improved parking facilities impact highway users' mode choice. Sixty percent of respondents are willing to leave their car in P+P lots near interchanges. The results also show that P+P lots can increase the number of carpool users. It causes remarkable savings in terms of operating and external costs because of the reduction in total distance and time travelled by personal vehicles as well as parking demand reduction in cities. At the moment, especially in Central Europe, it is easier to invest in a "demand reduction" infrastructure than to increase the capacity of infrastructure. Therefore, P+P lots could be a "win-win" situation for both users and operators.
... It is commonly recognised that HOV lanes can carry more people than general purpose (GP) lanes during peak hours. However, low occupancy vehicle (LOV) drivers recently complain about underused HOV lanes in certain time periods when other GP lanes are congested [1][2][3], HOV lanes were found to increase congestion in the HOV networks of Bay area by underutilising the lane capacities by about 400 vehicles per hour [3]. To improve the inefficiency utilisation of the system and provide more reliable trips, many transportation agencies are considering setting up HOT lanes. ...
... It is commonly recognised that HOV lanes can carry more people than general purpose (GP) lanes during peak hours. However, low occupancy vehicle (LOV) drivers recently complain about underused HOV lanes in certain time periods when other GP lanes are congested [1][2][3], HOV lanes were found to increase congestion in the HOV networks of Bay area by underutilising the lane capacities by about 400 vehicles per hour [3]. To improve the inefficiency utilisation of the system and provide more reliable trips, many transportation agencies are considering setting up HOT lanes. ...
Article
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To utilise high occupancy vehicle lanes better, high occupancy toll (HOT) lanes are introduced to counter against congestion on the urban highways. In such system, low occupancy vehicles (LOVs) are allowed to pay a toll and access to HOT lanes from general purpose (GP) lanes, so that the toll rate plays a key role in dynamically allocating LOVs over the HOT and GP lanes to improve the overall system performance. First, this study presents an improved random forest (RF) method to build the lane choice behaviour prediction model. Then, by using the 5 min historical traffic and toll data collected from Interstate 405 in the USA, the improved RF combined with cross-validation and grid search shows the highest accuracy of 88.7%, which is better than other four methods. Furthermore, a novel nested model with two levels is proposed to optimise the toll rates under different real-time traffic conditions. For the nested model, the experimental results show that the proposed dynamic pricing strategy can decrease the total delay and improve the efficiency significantly. To realise the pricing strategy, some Intelligent Transportation System technologies for HOT lane systems are described in detail and designed as the fundamental of the pricing strategy. © 2019 Institution of Engineering and Technology. All Rights Reserved.
... Passenger capacity means the number of passengers passing through a road section. To measure this indicator, average car occupancy is set to 1.3 passengers [36,37], and average bus occupancy is set to 28 passengers [38,39]. Initializing inputs for the variables as follows: t depart � 120 s, l cd � 300 m, p rand � 0.25, p in � 1, p out � 0.7. Figure 14 reduced. ...
Article
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Bus lanes with intermittent priority (BLIPs) are lanes where general traffic is required to give way to approaching buses. BLIPs can improve the reliability of bus services and help maximize the use of road resources. It can be seen as an innovative sharing mobility, such as carsharing, carpooling, and lane sharing. However, implementation of BLIPs has never been feasible until vehicle communications could accommodate the idea. Vehicle-to-vehicle (V2V) communications have broad application prospects in the deployment of BLIPs. This paper develops a two-lane cellular automaton (CA) model to simulate BLIPs and assesses the benefits of connected vehicles for bus operation. In the model, lane-changings are asymmetric with an improved mandatory BLIP lane-changing rule underlying. The effects of BLIPs are explored through numerical simulations, including BLIPs’ impacts on neighboring lanes, travel time saving, fuel consumption, and the punctuality rate of buses. Analysis of traffic flow characteristics of corridors using BLIPs reveals that there is a strong connection among the bus departure interval, clear distance, and road capacity.
... With the goal of encouraging certain types of travel modes, such as carpooling or transit, Dedicated Lane (DL) management has become prevalent on both highways and arterial roads as a way to speed up carpooling vehicles and buses (Brown, 2020). DLs include High Occupancy Vehicle (HOV) lanes (Kwon & Varaiya, 2008), High Occupancy Toll (HOT) lanes (Fielding et al., 2003), managed lanes (Kuhn & Jasek, 2003), exclusive bus lanes (EBL) (Lin et al., 2012), etc. ...
Article
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Dedicated Lanes (DLs) have become prevalent on highways and arterial roads as they help accelerate carpooling vehicles or buses. However, capacity is wasted if the penetration rates of these vehicles with priority are low. Wasted capacity can be utilized optimally by implementing Vehicle-to-Everything (V2X) technology and granting General-Purpose (GP) vehicles the ability to traverse on DLs. However, existing research on flexible DLs has mostly focused on preset, static operating rules. In this study, we propose a true, active DL management strategy named Dedicated Lane with Intermittent Priority (DLIP) that operates at the vehicle level. An Optimal Right of Way Allocation (ORWA) model is proposed that maximizes the benefits of allowing GP vehicles into the DLs. To validate the proposed strategy, a simulation model based on VISSIM was developed. Results under various demand scenarios demonstrate that the proposed strategy outperforms traditional DL management strategies in terms of overall productivity, with improvements ranging from 10% to 25%.
... Por su parte, las prohibiciones de circulación en determinados días pueden acabar elevando el total de vehículos en circulación (de Grange y Troncoso, 2011). Los carriles para vehículos de alta ocupación tampoco proporcionan los incentivos suficientes (Know y Varaiya, 2008), mientras que la expansión infraestructural es costosa y suele generar aumentos de tráfico (Goodwin, 1996). ...
Book
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El Informe, de 800 páginas, da cumplimiento a la Resolución de creación del Comité, conforme a la que la futura reforma tributaria debe adecuarse a la realidad económica del siglo XXI y garantizar un sistema tributario “más equitativo, progresivo, justo y que incorpore la imposición medioambiental, digital y la perspectiva de género”. Se trata, con ello, de “sentar las bases para una reforma tributaria estructural a medio y largo plazo que modernice y aumente la eficiencia del sistema tributario de nuestro país”. En suma, el objetivo del Libro Blanco es servir de fundamento para una reforma del sistema tributario que garantice la sostenibilidad de las finanzas públicas, de manera que pueda responder a la financiación de los gastos públicos, contribuyendo a reducir el déficit estructural y al mantenimiento del Estado de Bienestar.
... Por su parte, las prohibiciones de circulación en determinados días pueden acabar elevando el total de vehículos en circulación (de Grange y Troncoso, 2011). Los carriles para vehículos de alta ocupación tampoco proporcionan los incentivos suficientes (Know y Varaiya, 2008), mientras que la expansión infraestructural es costosa y suele generar aumentos de tráfico (Goodwin, 1996). ...
... In some countries, road traffic rules supported the carpooling system with HOV lanes (Highoccupancy vehicle lane). Kwon and Varaiya (2008), Menedez and Daganzo (2007), have investigated their effectiveness. According to Bruno P. Bruck et al. (2016), carpooling has a positive impact on the environment. ...
Article
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Reducing the costs and environmental impact of passenger car transport is very important. However, people are often more interested in money savings. Carpooling is a passenger transport system in which the driver shares a seat or seats in his car. The system consists of a certain number of vehicles, users, and a coordination element. It is very different from Carsharing, in which the whole vehicle is shared. It is not easy to quantify the economic benefits of a carpooling system for the driver. The third chapter shows the cost calculation of operating a private passenger car. Currently, drivers can use various booking systems that recommend the optimal price for transporting one person for a specific distance. It is approximately possible to determine what travel fare the driver obtains in the carpooling. These revenues are in the fourth chapter of the article. The main goal is to evaluate the economic efficiency of carpooling by comparison of calculated costs and revenues. It shows the exact methodology of how it is possible to estimate the economic benefits of the carpooling system for individuals.
... However, HOV lanes are criticized for their effectiveness, which is context-dependent. In research that evaluates the Californian HOV system, researchers found that HOV lanes are underutilized, slower than expected, while only offer a slight improvement in travel time and congestion (Kwon & Varaiya, 2008). Regulation is also a concern, with evidence in several countries that people cheat to be able to drive in an HOV lane. 2 In contrast to HOV lanes, carpooling lines are conventional routes where people rideshare spontaneously. ...
Thesis
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Modern societies are faced with multiple challenges caused by widespread car usage. In urban cities, too many cars on the road are creating traffic jams, air pollution, and noise. In rural villages, residents are becoming more and more dependent on cars, limiting the mobility rights of a vulnerable population. Ridesharing could be a solution to both challenges. The thesis adds to the understanding of the behavior of ridesharing participants. The first two papers are two field experiments with Ecov on the monetary and prosocial motivations of drivers. For trips of very short distances, prosocial motivations are more salient for promoting the practice, while for middle-distance trips, monetary incentives are more salient. However, putting a very high monetary incentive does not outperform a lower but sufficient one. The third paper examines the impact of the French railway worker strike in 2018 on long-distance ridesharing using data from BlaBlaCar. An average strike day induces the ridesharing seat supply to increase by 7% and the seat demand to increase by 29%. The ridesharing passengers' consumer surplus also increases by 17,753€ during an average strike day across the whole of France.
... eir study is thus limited to tolled roads. Furthermore, there exists skepticism around the effectiveness of HOV lanes in the transport community [20,21]. A recent report indicates that even though the number of HOV lanes has increased in the US, the number of carpooling commuters is declining and the enforcement of the HOV lanes remains a challenge [22]. is suggests that further research is needed to efficiently deploy incentives for promoting ridesharing. ...
Article
Full-text available
Traffic congestion is largely due to the high proportion of solo drivers during peak hours. Ridesharing, in the sense of carpooling, has emerged as a travel mode with the potential to reduce congestion by increasing the average vehicle occupancy rates and reduce the number of vehicles during commuting periods. In this study, we propose a simulation-based optimization framework to explore the potential of subsidizing ridesharing users, drivers, and riders, so as to improve social welfare and reduce congestion. We focus our attention on a realistic case study representative of the morning commute on Sydney’s M4 Motorway in Australia. We synthesize a network model and travel demand data from open data sources and use a multinomial logistic model to capture users’ preferences across different travel roles, including solo drivers, ridesharing drivers, ridesharing passengers, and a reserve option that does not contribute to congestion on the freeway network. We use a link transmission model to simulate traffic congestion on the freeway network and embed a fixed-point algorithm to equilibrate users’ mode choice in the long run within the proposed simulation-based optimization framework. Our numerical results reveal that ridesharing incentives have the potential to improve social welfare and reduce congestion. However, we find that providing too many subsidies to ridesharing users may increase congestion levels and thus be counterproductive from a system performance standpoint. We also investigate the impact of transaction fees to a third-party ridesharing platform on social welfare and traffic congestion. We observe that increasing the transaction fee for ridesharing passengers may help in mitigating congestion effects while improving social welfare in the system.
... Second, reductions in the already limited road capacity are observed, because usually a general-purpose lane that was open to all commuters is converted into a HOV lane, causing even more severe congestion. Some have argued that while HOV lanes provide faster travel times, the time differential between the HOV and the general purpose lanes is minimal and insignificant (Kwon and Varaiya, 2008). Still, others claim that HOV lanes offer substantial travel time reductions in some cases and, more importantly, provide higher travel time reliability for HOV drivers (Fontes et al., 2014;Samimi et al., 2016). ...
Article
We assess the case of the abrupt discontinuation of the three-in-one policy, a high-occupancy vehicle (HOV) restriction, in Jakarta, with the objective of mapping potential interdependencies in the transportation system. Statistical investigation of the passenger volume in the bus rapid transit (BRT) system in the whole city before and after the policy change revealed a significant increase in the number of passengers during peak hours, especially in the evening period. The extent of the increase, however, depended on whether the area had been subject to the initial policy restriction. The case of sudden discontinuation of the three-in-one policy in Jakarta illustrates how a change in policy aimed at a single transportation mode may spill over to alternative transportation modes. The importance of acknowledging the systemic nature of urban transportation systems when altering policies intended to discourage the use of a single transportation mode within the larger transportation network is discussed.
... ). Their services are available in most metropolitan cities, like Kolkata, Mumbai, New Delhi, and Chennai.A study in the United States demonstrated that 1% of private vehicles joining carpooling can save three billion liters of gas and 10% can save 28 billion liters in one year(Kwon and Varaiya 2008). As expressed by the State of European Car-Sharing report, carpools show 15-25% fewer CO2 discharges in comparison to private vehicles (MOMO 2010). ...
... Many researchers have examined their impact. For example, Kwon and Varaiya (2008) estimated the impact of HOV lanes utilizing over 700 detectors in California. They concluded that HOV lanes are substantially underutilized and that 81% of detectors on HOV lanes measured traffic flows below 1,400 vehicles per hour per lane during the PM-peak hour. ...
Article
Managed lanes (MLs) offer public infrastructure owners a key policy lever for reducing the financial burden of road expansion while managing induced travel demand. ML’s impact varies depending on the operational method adopted. Previous literature has focused on only one option’s optimum toll estimation, operational strategies, or impacts at a time. In this study, we provide the first detailed network-wide comparisons of MLs that include travel time, vehicle-miles-traveled (VMT), general-travel cost, fuel consumption, and emissions. We embed a toll-choice model within a four-step travel demand model considering drivers’ value of travel time (VOTT). The study uses existing high-occupancy-toll (HOT) lanes and the surrounding network in the Dallas-Fort-Worth, Texas, area as a case-study area. We find the following: (1) HOT lanes are the preferred option providing the highest travel-time savings; (2) the all-tolled option performs the best at the corridor level. It reduces corridor travel time by around 20%. However, lower traffic volume on tolled lanes generates lower overall network performance; (3) high-occupancy-vehicle (HOT) performs the worst and is similar to the do nothing option; and (4) both priced options, all-tolled and HOT, generate the smallest total emissions and fuel consumption.
... However, most papers attempt to quantify the benefits of HOV lanes and determine whether they exist at all via empirical investigation. In-depth surveys on these approaches are, for instance, provided by Kwon and Varaiya (2008) and Shewmake (2012) . From an operational research perspective, the main optimization problems that are related to HOV lanes are congestion pricing if the lanes are also accessible when paying a toll (see Small & Yan, 2001;Verhoef & Small, 2004;Yang & Huang, 1999 ) and traffic flow modeling with queuing models (e.g., Cassidy, Jang, & Daganzo, 2010 ) or simulation (e.g., Menendez & Daganzo, 2007 ). ...
Article
High-occupancy vehicle (HOV) lanes are restricted traffic lanes that are reserved for vehicles with multiple car occupants. Depending on the current number of passengers, a driver must either travel slower on the often-congested general-purpose lane or can access the faster HOV lane. In this paper, we provide optimization approaches for matching supply and demand when building carpools along HOV lanes. In current applications, carpools form spontaneously in slugging areas where potential passengers queue. However, internet-enabled mobile phones that are connected to a central ride sharing platform enable dynamic carpool formation based on sophisticated scheduling procedures. We investigate various versions of the carpool formation problem. The computational complexity is analyzed in depth, and suitable solution procedures are developed. These procedures are applied to quantify the benefit of an optimized carpool formation process. In a comprehensive computational study, we compare our optimization approaches with spontaneous ride sharing and show that substantially better solutions for all stakeholders can be obtained.
... To address this under-utilization issue of carpool lanes, two alternative improvement schemes have been proposed and put into practice (Varaiya, 2007). One is converting carpool lanes to high-occupancy toll (HOT) lanes which charge solo drivers to use the carpool lanes. ...
Article
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Carpooling as one of demand management measures is effective in reducing highway congestion. Recent studies have shown that an appropriate spatial allocation of bottleneck capacity between carpool lane and general-purpose lane can lead to peak-spread of the morning commuters' departure time and reduce the system's total trip cost. What is not clear however is whether temporal allocation of bottleneck capacity can also be effective and if so, what the impact would be, and furthermore what the combined effects of temporal-spatial allocation of bottleneck capacity would be. This paper investigates the impacts of a temporal allocation of bottleneck capacity, when carpool lane is available only within a reserved time window, and a joint temporal-spatial capacity allocation, on morning commute patterns. User equilibrium commute patterns are derived for both the temporal-only and the joint temporal-spatial capacity allocation schemes, along a highway corridor with two driving modes: solo driving and carpooling. The extra costs associated with carpooling are considered alongside of travel time and schedule delay costs. We identify three different cases representing the relative barriers and attractions of carpooling to commuters, and we show that the optimal capacity allocations are sensitive to the accurate estimation of the commuters' extra carpool cost. To assist in evaluating the difference between a non-optimal and the optimal temporal-spatial allocation schemes, we derive analytically the upper bounds on the efficiency loss and present numerical illustrations on how the upper bounds vary with the different operational and behavioral variables.
... One of the main purposes to introduce lane reservation concept was to promote and increase attractiveness of the public transit [2][3]. The concept of designated lanes for high occupancy vehicles (HOV) is another concept that introduced lane reservation aspect to improve overall mobility of roadway facilities [4][5][6][7]. Following the same conceptual framework, many researchers in the past decade investigated implementation and promotion of automated driving using lane reservation approach [7][8][9], however, not too many researchers offered implementation strategy that would help roadway operators estimate impact of lane reservation on overall signalized corridor mobility under imperfect market penetration of automated vehicles. ...
Preprint
An automated vehicle refers to a vehicle that can achieve a safe movement on a roadway facility without the influence of a human driver. With emerging trend of the connected vehicle concept over the past decade, numerous state-of-the-art applications focusing on automated vehicle-based intersection control have been proposed. The main purpose of this study is to estimate and evaluate impact of designated lanes for automated vehicles and recommend some viable lane configuration scenarios for signalized urban arterials. The automated driving was simulated in PTV Vissim using trajectory-driven control strategy. The concept evaluation through microsimulation reveals significant mobility improvements compared to operational scenario without lane reservation. Findings imply that for signalized corridors observed in this study, total travel time reductions are ranging from 5.1% to 19.4% depending on C/AV market penetration, and test-bed configuration parameters.
... Many studies have concerned the low utilization of HOV lanes. Kwon and Varaiya (2008) collected speed and flow measurements from 700+ stations during peak hours of 128 weekdays in 2005, and found 81% of HOV lane flow rates are below 1400 vehicles per hour per lane. In this case, it is necessary to find a strategy to improve the freeway performance. ...
Thesis
In this thesis, we propose one approach to determine the real-time tolling strategy for high occupancy toll(HOT) lane, and calibrate driver's value of time (VOT) as well. There are two goals of operating HOT lane, one is to maximize the freeway's, and another one is to maintain the free flow speed. We use queue length to track the traffic dynamics, and the point queue model is used. And with the application of a proportional-integral-derivative (PID) controller, we can calculate the pricing rate for HOT lane and calibrate driver's VOT. Simulation results and comparison with previous studies are provided.
... The simplicity of this model makes it more effective by reducing traffic congestion, whereupon the ridesharing form has become more popular. Another considerable benefit of slugging is not just cost-saving but to drive on High-Occupancy Vehicle (HOV) lane [26]. Remark 1. Slugging was originally developed for commuters not entrepreneurs. ...
Article
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Ridesharing has gained much attention as a solution for mitigating societal, environmental, and economic problems. For example, commuters can reduce traffic jams by sharing their rides with others. Notwithstanding many advantages, the proliferation of ridesharing also brings some crucial issues. One of them is to rideshare with strangers. It makes someone feel uncomfortable or untrustworthy. Another complication is the high-latency of ridesharing group search because users may want to receive the result of their requests in a short time. Despite continuous efforts of academia and industry, the issues still remain. In this paper, for resolving the obstacles, we define a new problem, l-cohesivem-ridesharing group (lm-CRG) query, which retrieves a cohesive ridesharing group by considering spatial, social, and temporal information. The problem is based on the three underlying assumptions: people tend to rideshare with socially connected friends, people are willing to walk but not too much, and optimization of finding good groups is essential for both drivers and passengers. In our ridesharing framework, queries are processed by efficiently taking geo-social network data into account. For this purpose, we propose an efficient method for processing the queries using a new concept, exact n-friend set, with its efficient update. Moreover, we further improve our method by utilizing inverted timetable (ITT), which grasps crucial time information. Specifically, we devise time-constrained and incremental personalized-proximity search (TIPS). Finally, the performance of the proposed method is evaluated by extensive experiments on several data sets.
... The technique of (HOV) lanes is a disputable way to eliminate traffic congestions [2,3], for the reason that HOV will succeed to eliminate congestions, only if traffic congestions refuse to go away. I. e. there is a need for ongoing congestions in the general purpose lanes so as to convince the drivers to shift to the HOV lane, otherwise the HOV lanes will have no effect [4]. ...
... In addition, exclusive lanes, a traffic management approach, were widely applied to solve the traffic chaos brought by mixed traffic. e implementation of exclusive lanes such as bus lanes and high-occupancy vehicle (HOV) lanes was beneficial [24][25][26]. Learning from the previous successful experience, the CAV-exclusive lane is a feasible approach to reduce the interaction between CAVs and MVs and to improve the performance of mixed traffic [27][28][29]. Ma and Wang [30] developed a four-lane heterogeneous CA flow model and studied the impact of exclusive lanes for CAVs on the overall flow throughput. ...
Article
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Connected and autonomous vehicles (CAVs) have become the highlights of traffic. Researchers in this field have proposed various traffic management measures to enhance the capacity and efficiency of traffic with CAVs, especially mixed traffic of CAVs and manual vehicles (MVs). Exclusive lane setting is included. However, exclusive lane policy-related researches for mixed traffic of CAVs and MVs were very limited, and the influence of number and location of exclusive lanes on the mixed traffic was unclear. To fill this gap, this paper aims to study the influence of different exclusive lane policies on mixed traffic and provide recommended lane policies under various traffic volumes and CAV penetration rates. Freeways with two lanes and three lanes in a single direction were taken into consideration, and sixteen lane policies were proposed. Then different lane policies were simulated with a new proposed cellular automata (CA) model, and properties including flux, average speed, and CAVs degradation were analyzed to evaluate the traffic efficiency of each lane policy. The results show that CAV exclusive lanes can improve the capacity, while MV exclusive lanes seem helpless for capacity improvement. Seven lane policies, including GC, GM, and CM for two-lane freeways and GCG, CGC, and CCM for three-lane freeways, outperform the others in terms of average speed. In addition, exclusive lanes can reduce the probability that CAVs degenerate to AVs. Our findings may help to optimize freeways’ lane policies and improve the efficiency of heterogeneous traffic mixed with CAVs and MVs.
... The current study tries to address a problem of under-utilized HOV facilities. For future 37 studies, more modelling and behavioral analysis should be conducted to identify why this is 38 happening. ...
Conference Paper
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High-Occupancy Vehicle (HOV) facilities aim to move more people and, hence, improve the overall performance of the highway segment by reducing travel time, increasing average operational speed, and reducing traffic congestion. Although many studies have been conducted on HOV lane performance, the HOV facility performance during the inactive time, typically off-peak period, has received limited attention. During HOV inactive time, HOV lanes are typically reverted to and treated as general purpose (GP) lanes. A key aspect of the study presented herein focuses on the performance of HOV under such conditions, namely, the observed driver preferences and use patterns of HOV lanes under congested/ uncongested condition and during HOV active/inactive time. Data of Part-time HOV lanes from radar detection system (RDS) near Nashville, Tennessee were collected and evaluated. The findings of the study include (1) during congested condition in HOV active time, HOV lanes has lower speed and higher flow than adjacent GP lanes, (2) HOV lanes tend to be underutilized in uncongested area during HOV active, and (3) drivers are reluctant to use HOV facilities during inactive time and weekends. This mean HOV lanes during HOV inactive time are underutilized and do not really work as GP lanes. They can almost be considered as “full-time” HOVs. Also, drivers are not willing to use HOV lanes unless they confront congestion. This study tries to address an HOV lane malfunction during the inactive time and uncongested time. For future studies, the authors will try to answer many questions about why this happens.
... HOV lanes are one kind of special-use lanes that enable vehicles with a predetermined number of passengers to bypass congested traffic in general purpose lanes, which have been widely installed along the crowded urban freeways to improve the overall mobility within metropolitan freeway systems (e.g. Varaiya and Han 2008). ...
Article
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Subscription bus services (SBS) is a convenient and low-carbon rapid transport mode for passengers’ daily commute. The network design becomes a vital problem because it closely relates to both operators’ profit and passengers’ daily convenient traveling. In this paper, a two-stage model is formulated to optimize the subscription bus services network design (SBSND). During the first stage we minimize the total service distance and the number of vehicles as a single target objective function; vehicle capacity utilization rate, service time, ratio of service distance and linear distance between origin and destination are limited by means of constraints. During the second stage we share the same objective function and similar constraints used during the first stage, but the parameter settings of the constraints are different. Correspondingly, a two-stage algorithm is also designed to solve the SBSND problem. Firstly, we obtain the possible service lines, match the passengers and bus capacity. Next, we use Dijkstra to obtain the shortest SBS operation lines. Finally, we form the SBS network. The three phases are the main processes about the algorithm during both stages. The comparison between existing SBS in Chengdu city and the optimized SBS shows the high efficiency of the optimization model and algorithm formulated in this paper: the operation line length increases from 250.6 to 300.9 km; only 40 passengers have no SBS after optimization; the average operation time is reduced from 56.8 to 50.2 min.
... Consideration of MLs and their effect on travelers has spurred numerous research studies addressing topics ranging from ML equity (Weinstein and Sciara 2004), to people's reactions to MLs (Burris et al. 2007), to ML effectiveness (Kwon and Varaiya 2008). One fundamental question linked to all of these issues is the question of, "Who uses MLs, and why?" Socio-demographic characteristics of travelers are important but are certainly not the only individual differences that could be of interest in better understanding travel behavior on MLs. ...
Article
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Managed lanes (MLs) are a tool to more efficiently operate segments of a freeway. As ML prevalence increases in the United States of America, it is important to understand travel behavior in a ML setting (i.e., lane choices and carpooling decisions). Socio-demographic and trip data, along with travel time and toll, have been commonly used in this endeavor. However, there are some travelers who pay to use the ML despite there being little to no improvement in travel time over the adjacent general purpose lanes. This gives rise to the possibility that psychological traits and characteristics are a greater influence on ML use than even travel time savings for some travelers. This research examined this issue through a set of largely transportation-framed psychological items. After an initial creation and refining process, 25 psychological items were included in a survey advertised in five cities with MLs. In addition to psychological items, trip and demographic questions, and three SP questions were included in the online survey. Mixed logit models were estimated based on survey responses obtained from three study areas. Models that included psychological items performed better (in terms of adjusted rho squared value and percent correctly predicted values) than models with only trip and demographic variables. Likewise, models including psychological items plus trip and demographic data performed best. This information may be useful for traffic and revenue estimating firms interested in potentially including psychological items in future ML surveys intended to facilitate better estimation of ML use.
... Alongside, the commonly-adopted policy, particularly in western industrialized countries, is High Occupancy Vehicle (HOV) lanes, which aim to improve travel time reliability and safety for passenger vehicles with or beyond required occupancy (e.g. two or three occupants). Nevertheless, both theoretical and empirical studies have shown that the supposed benefits of HOV lanes are often difficult to achieve [13], and the small travel time savings generated from the lanes do not provide a statistically significant carpooling incentive [16]. In sum, there is still a lack of consensus for the effective measures that best boost carpooling, particularly in developing countries, calling for further investigation into the methodologies that can assist governments in designing more efficient measures to promote the carpooling demand, which is of vital significance for the mitigation of environmental pollutants and the sustainable development of urban traffic. ...
... A high proportion of two people "family-pools" (Zhang, Liu, Wang, & Yang, 2017) dramatically reduced the efficiency of HOV lanes that were built with the expectation of carrying three persons or more per vehicle (Poole & Balaker, 2005). Kwon and Varaiya (2008) discovered that most HOV lanes are under-utilized in California. About 81% of HOV lanes carry below 1400 vehicles per hour per lane during the peak hour. ...
Article
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Carpooling is an effective solution for traffic congestion. However, social obstructions (lack of trust) and cost obstructions (high commute cost) are still two major challenges for promoting carpool activities. In this paper, a social-route-network carpooling model (SRNC model) is proposed. The model combines commuters' social networks and commute route networks to provide optimization on both trust and cost in different carpooling teams. The trust optimization improves the social comfort between commuters by introducing the concept of degrees-of-separation and the user preference. The cost optimization reduces the total commute distance with integer programming model. Finally, both trust and cost are balanced in a unified model—the SRNC model. By using the Twitter social network and the Washington, D.C. road network, the SRNC model is evaluated. Results demonstrate a significantly improvement of the trust (around decuple) with a small loss in route cost (around 6.3%) as compared to a route-network-only carpooling model.
... Dynamic shoulder lane use is a type of managed lane strategy that allows shoulders to operate temporarily as a high occupancy toll (HOT) lane during peak hours and/or non-recurrent congestion (i.e. incidents, reduction in travel time (Kwon and Varaiya, 2008) were the common problems of HOV lanes. HOT lanes are able to mitigate congestion by allowing SOVs to use this lane by paying a toll when additional capacity exists in HOT lanes. ...
Article
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This article presents a comprehensive framework that optimizes traffic management measures to reduce emissions and fuel consumption and evaluates their operating and secondary environmental impacts. A new managed lane strategy is presented that minimizes the total passenger travel time on the freeway. This managed lane focuses on simultaneously optimizing toll schemes on the high occupancy toll (HOT) lane and the operation of the general purpose (GP) lanes. With reduced congestion and thus reduced number of acceleration and deceleration events associated with stop-and-go traffic, fuel efficiency increases and emissions are reduced. PARAMICS microscopic traffic simulator, which considers the behavior of individual vehicles (e.g., acceleration, deceleration, and lane changing behavior) is used to collect traffic performance and emission data for estimating mobility and emissions measures (i.e., operating phase). While previous studies only focused on operating phase impact, this study uses a Leontief input-output (I-O) model to establish the financial flow between industries to capture the large-scale environmental impacts of HOT lane deployment (i.e., secondary impact). The core of the new evaluation approach lies in its capability to provide a more thorough assessment of the environmental impacts of traffic management schemes by quantifying the impacts associated with the interplay between the activities of various sectors and the transportation industry. The I-O model is utilized to assess the indirect impacts of induced demand generated from network improvements and evaluate the environmental impacts of HOT lane deployment in regional economies. The developed approach is applied to The City of Calgary. The results of the study show that the traditional approaches that only evaluate the operating phase impacts of transportation strategies considerably overestimate the reduction of greenhouse gas (GHG) emissions.
... Alongside, the commonly-adopted policy, particularly in western industrialized countries, is High Occupancy Vehicle (HOV) lanes, which aim to improve travel time reliability and safety for passenger vehicles with or beyond required occupancy (e.g. two or three occupants). Nevertheless, both theoretical and empirical studies have shown that the supposed benefits of HOV lanes are often difficult to achieve [13], and the small travel time savings generated from the lanes do not provide a statistically significant carpooling incentive [16]. In sum, there is still a lack of consensus for the effective measures that best boost carpooling, particularly in developing countries, calling for further investigation into the methodologies that can assist governments in designing more efficient measures to promote the carpooling demand, which is of vital significance for the mitigation of environmental pollutants and the sustainable development of urban traffic. ...
Article
As an eco-friendly and convenient transportation mode, mobile internet-based carpooling has achieved mushroom growth in many cities in recent years. Theoretical studies have verified that ridesharing is not only beneficial to drivers and passengers but particularly to the environment. Nevertheless, the exact impact of ridesharing on energy consumption and exhaust emission has been barely explored based on real carpooling data. In this study, using massive mobile internet based carpooling data offered by DiDi Company, a trip-specific model was initially proposed to study the intrinsic mechanism of carpooling services and then estimate the fuel savings of individual carpooling trip. According to the estimation results, delicacy subsidy strategies under the Personal Carbon Trading scheme were suggested to guarantee the moderation and equity in promoting carpooling services. The developed methodology was further tested in the case city of Beijing and associated results showed that ridesharing could be a feeder for public transit to support the commuting demands of workers living in suburban. More importantly, the fuel savings of ridesharing are considerable, every trip saving 1.23 L on average, and the carbon subsidies are moderate, per trip reaching ¥5.38 with the strictest subsidy ceiling. From the spatial-temporal perspective, the Chaoyang district and the daily peak-hour period generate the largest number of both ridesharing orders and fuel savings. All the results demonstrate that the trip-specific model has the advantages of delicacy, reliability and accuracy, which could facilitate the estimation on the trip-specific fuel savings and the formulation of carpooling promotion strategies.
... Menendez and Daganzo (2007) showed that HOV lanes may smooth flow through certain bottlenecks by dampening lane changing activity. On the other hand, Kwon and Varaiya (2008) and Chen et al. (2005) found that single-HOV lanes suffer a 20% capacity 1 3 drop and provided less time saving compared to adjacent general purpose lanes. The authors attributed these results, obtained from peak hour traffic data from 700 + loop detector stations installed on California's HOV system, to overtaking restrictions on such facilities. ...
Article
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Urban transit systems consist of multiple modes of transport of which cars and buses make up the largest portion, particularly in developing countries. Thus, theories on the best means of allocating existing road spaces for cars and buses in city-centers and suburban corridors in order to improve operational transport efficiency has become a frontier research topic. Today, bus priority (BP) methods, as one of the most widely used Public Transport Priority (PTP) strategies, are commonly recognized as effective in lowering traffic congestion and reducing bus travel times. PT authorities, urban planners/designers, and researchers dealing with PT issues (i.e. buses), need to investigate existing BP methods in detail and assess relevant research before setting about designing or implementing new policies. Of course, evaluating such studies is a time-consuming process. In order to address this constraint, the present study proposes a general typology of existing BP methods and evaluates the challenges and requirements regarding their implementation by conducting a comprehensive literature review of existing studies related to PTP. Academic papers (theoretical, analytical, and simulation-based), technical reports, and design manual/guidelines in the context of both developed and developing countries have been searched as part of the literature review process. The study concludes by proposing two comparative summary tables of all spatial bus priority schemes in terms of “min. requirements to justify BP schemes” and “advantages and disadvantages of time-based and spatial BP treatments”. These may provide engineers, urban planners or transit policy-makers with an accessible guide with which to refer in the evaluation stage. However, future research is recommended in order to bridge existing gaps concerning conditions required for the successful implementation of spatial bus priority strategies.
... They are becoming more and more common in metropolitan freeways, with the objective of increasing the vehicle occupancy and promoting collective transportation and car-pooling. However, their effectiveness depends on their configuration [31]. It has been proven that in order to maximize their benefits, HOV lanes should be ordinary lanes that turn into HOV lanes only when necessary ( Figure 2a). ...
Article
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Technological advances revolutionize industrial processes, science, communications, and our way of life. However, developed societies have reached a stage in which the fascination with technological innovations often results in their indiscriminate consumption. In this paper, road traffic is used as a line of argument to demonstrate that the random introduction of technology does not imply benefits to society. Particularly, it is analyzed why some of the potential benefits of technological progress are lost in fields such as traffic monitoring, data handling, and traffic management, or in sustainable mobility initiatives, such as the introduction of electric vehicles or the implementation vehicle sharing projects. The risks faced in the future advent of autonomous vehicles are also discussed, and ideas for improvement suggested. A critical reflection on other transportation modes that are expected to be realized in the near future is included as well. The performed analysis evidences that the potential improvement in personal mobility will not become a reality if it exclusively relies on the latest technological devices, in line with consumers’ fantasies or economic interests. This is a statement that could be generalized to many other fields. The implementation/consumption of a particular technology should not be an objective in itself, but a tool to bring benefits to society.
Article
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For the purpose of determining whether vacant taxis are supposed to use high-occupancy vehicle (HOV) lanes, this paper builds a framework to explore the performances of a network before and after vacant taxis use HOV lanes and to detect the optimal deployment of HOV lanes. We use a variational inequality (VI) to describe travelers’ mode choice following a logit model and the route choice abided by the user equilibrium principle on the network. A simple network is adopted to explore the network performances when vacant taxis are allowed to use/forbidden from using HOV lanes. Then we propose a framework presented by a bi-level model for the optimal deployment of HOV lanes in which the lower level is the variational inequality and the upper level aims at maximization of social welfare. This bi-level programming with a genetic algorithm combined with a surrogate assistant approach is applied to the simple network and a Sioux Falls network to analyze the network performances in the cases allowing/forbidding vacant taxis from using HOV lanes. The results reveal the paradox that social welfare may decrease when allowing vacant taxis to use HOV lanes compared to when forbidding vacant taxis from using HOV lanes. Considering optimal HOV lane deployment, this paradox still exists. However, it does not always happen due to the different parameters, e.g., flag–fall price. Therefore, the qualification of vacant taxis to use HOV lanes depends on the topology, attributes, and travel demand of the network. The results display that the models and the algorithm are effective in reality.
Article
Since the 1970s, high-occupancy vehicle (HOV) lanes have been a common policy instrument to mitigate traffic congestion. Yet, their effectiveness remains a controversial topic among researchers, policy makers, and the public. In this debate, a key unknown has been the impact of HOV lanes on commuters’ carpooling behaviors. This paper brings a new piece of evidence by offering a data-driven assessment of carpooling intent and adoption, using revealed-preferences data. We partner with Waze, a major carpooling platform, and leverage a natural experiment following the introduction of three HOV lanes in Israel in 2019. Using tailored treatment and control groups coupled with econometric analyses, we derive four main findings. First, HOV lanes bring new users to the carpooling platform, which contributes to alleviating the “cold-start” problem in the marketplace. Second, HOV lanes have a positive impact on carpool intent: the number of carpool offers sent by drivers increase manifold following the introduction of the HOV lanes. Third, HOV lanes have a disparate impact on carpool adoption: carpools increase significantly for two out of three HOV lanes. This result underscores the critical impact of HOV lanes design: it seems more beneficial to have round-trip HOV lanes (as opposed to one-way lanes) and two-passenger occupancy requirements (as opposed to three-passenger requirements). Last, HOV lanes have a broader impact, by increasing carpooling on non-HOV routes and shifting the travel behaviors of non-carpoolers. We conclude by discussing policy implications, highlighting collaboration opportunities between policy makers and digital carpooling platforms to enhance the design and operations of HOV lanes.
Thesis
Face à l’engouement suscité par le « véhicule autonome » depuis le milieu des années 2010, les pouvoirs publics locaux cherchent à préciser leur position et l’action publique à mener à moyen et long terme en la matière. En effet, les effets attendus de cette technologie, positifs, sur la sécurité et la circulation routières, mais aussi négatifs, sur le nombre de véhicule-kilomètres parcourus ou la fréquentation des transports en commun, s’inscrivent à l’échelle territoriale. Considérant l’incertitude inhérente à ces prévisions, le recours à l’évaluation ex ante est d’intérêt pour renseigner la décision publique locale. Cette thèse propose donc un cadre méthodologique pour une évaluation prospective et durable du véhicule autonome à l’échelle métropolitaine. La méthodologie définie est illustrée grâce à une « preuve de concept », consistant en une application à la Métropole de Rouen. Ainsi, trois scénarios d’introduction du véhicule autonome : véhicules personnels, taxis et système de rabattement sont étudiés grâce à une analyse multicritères qualitative et participative. Cette mise en œuvre montre l’utilité de recourir aux principes méthodologiques de l’évaluation prospective et de l’évaluation durable pour formaliser l’évaluation du véhicule autonome. Plus généralement, prospective et durabilité apparaissent comme des notions clés pour une gestion réfléchie et distanciée de l’introduction du véhicule autonome.
Chapter
Chapter 2 explores the social and economic developments that lead to the emergence of mobility-as-a-service. This chapter focuses on the outcomes and implications of the digital transformation, particularly how software has become the main source of value creation and competitive advantage in the automotive industry. Ongoing urbanization serves as a catalyst for creativity, innovation, and job creation but decades of a car-centered policy entail severe negative outcomes. This chapter explores the challenges of urbanization, the rise of superstar cities, and the promise of smart cities. It further delves into how younger generations like millennials or generation Z perceive and value other things than previous generations. They appear less car-crazed, but are also confronted with a striking intergenerational wealth gap, which influences mobility behavior on various levels.
Article
This article introduces a telematics-based traffic law enforcement and management system (SLEM), which leverages connected vehicle and telematics technologies. The system assigns each driver a real-time score that measures her/his driving performance. Using these driver scores, SLEM then adopts a personalized route guidance strategy that favors high-performing drivers by guiding them to less congested routes at the expense of low-performing drivers who are directed to alternative, slower routes. This routing strategy shifts the network traffic distribution pattern from the undesirable user equilibrium pattern to the system optimal pattern. Hence, SLEM not only incentivizes drivers to improve their driving performance but it also provides a mechanism to manage network congestion. A bilevel mathematical program and an efficient solution methodology were developed to derive SLEM’s optimal routing strategy. A set of experiments that was conducted to evaluate the performance of SLEM under different operation scenarios showed that the adoption of SLEM’s routing strategy reduced travel time during recurrent congestion situations by about 5%.
Article
This paper builds a novel framework for the cordon-based road reservation system to manage road traffic in urban areas, and the rules of reserving the right of way are established. Both the simulation experiment and the analytical modeling approaches offer evidence that the reservation system performs better than the basic system and some types of pricing systems. Considering two different types of vehicles (i.e., reserved and unreserved vehicles) and a general link cost function, we conduct three types of experiment simulations, including the basic system, the reservation system, and the pricing system. Although the severity of traffic congestion is mitigated inside the cordon both in the reservation and pricing systems, the reservation system shows the best network performance from the traffic indicators provided by the simulation software. In the analytical modeling approach, the Frank-Wolfe algorithm with a modified Bureau of Public Road function is used to analyze the road reservation scheme, and results agree with the expected effectiveness of the reservation both in the aspect of the total system travel time and the equilibrium of the traffic flow in the road network. Finally, practical issues about the application of the road reservation system are discussed.
Article
Managed lanes are expected to reduce congestion and, potentially, vehicle emissions. Usually, planning agencies select lane management strategies first and foremost to improve regional mobility. Furthermore, transportation projects are regulated by the Clean Air Act towards the overall regional emission levels and project-level (or corridor-level) pollutant concentrations. The present study aimed to develop and implement an optimal integrated transportation and emissions modeling platform to evaluate regional vehicle emission and pollutant dispersion impacts and their significance for adding a managed lane facility to the roadway network. The case study examined the Loop 375–Border Highway West toll project in El Paso, Texas, under five proposed lane management strategies. Results confirmed the addition of a priced facility can provide congestion relief at the corridor level and cause some rerouting in other parts of the region. However, they do not appear to substantially reduce regional greenhouse gases and criteria pollutant emissions. The findings of the current study provide further insight within a regional context into selecting a transportation project and its true emission savings and air quality benefits.
Article
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This article analyses the reasons for the introduction of the Regional Fuel Tax (RFT) under the Land Transport Management Amendment Act 2018. It examines the economic and social costs of congestion, the role of environmental and fuel tax, and fuel demand elasticities. The article briefly assesses the underlying political influences and viewpoints behind the implementation of the current and potential future regional fuel taxes. The reference to various studies in the present research shows that the RFT scheme was implemented to generate significant revenue, which has been earmarked for public transport and infrastructure projects within Auckland to reduce congestion and pollution. Further, the article demonstrates that communicating the functioning of the RFT to the Auckland public with available evidence such as reduced congestion, air pollution, and health costs, improved atmospheric visibility and quality of life will help the Labour government to counter some of the claims that opponents of the tax put forward. While issues exist in the regressivity and exclusions in the RFT, it is asserted, however, that to correct externalities, designing a RFT based on the social cost of externality would be the right approach and would undoubtedly make a significant difference to our environment
Conference Paper
Road pricing has been advocated for decades as an efficient way of reducing congestion since the 1920s. In the U.S., there are several types of managed lanes, and the high-occupancy-toll (HOT) lane is an application of road pricing on freeway. At the same time, value of time (VOT) is a key factor when deploying congestion pricing. In this study, we propose one new approach to estimate drivers' VOT and determine the real-time tolling strategy for HOT lane simultaneously when lane drop occurs downstream of freeway segment. There are two goals of operating HOT lanes, one is to maximize the freeway's throughput, and another one is to maintain the free flow speed. The traffic state variables used in this paper is the queue length on HOT lane and turning influx of "paid" single-occupancy-vehicles (SOVs). The traffic dynamics is described by a point queue model. When the HOT lane is operated at optimal, we can use feedback control algorithm to estimate drivers' VOT; and the pricing rate for the HOT lane is calculated by the product of estimated VOT and travel time difference of two types of lanes. Simulations results are provided to validate our approach.
Article
For the transport sector, promoting carpooling to private car users could be an effective strategy over reducing vehicle kilometers traveled. Theoretical studies have verified that carpooling is not only beneficial to drivers and passengers but also to the environment. Nevertheless, despite carpooling having a huge potential market in car commuters, it is not widely used in practice worldwide. In this paper, we develop a passenger-to-driver matching model based on the characteristics of a private-car based carpooling service, and propose an estimation method for time-based costs as well as the psychological costs of carpooling trips, taking into account the potential motivations and preferences of potential carpoolers. We test the model using commuting data for the Greater London from the UK Census 2011 and travel-time data from Uber. We investigate the service sensitivity to varying carpooling participant rates and fee-sharing ratios with the aim of improving matching performance at least cost. Finally, to illustrate how our matching model might be used, we test some practical carpooling promotion instruments. We found that higher participant role flexibility in the system can improve matching performance significantly. Encouraging commuters to walk helps form more carpooling trips and further reduces carbon emissions. Different fee-sharing ratios can influence matching performance, hence determination of optimal pricing should be based on the specific matching model and its cost parameters. Disincentives like parking charges and congestion charges seem to have a greater effect on carpooling choice than incentives like preferential parking and subsidies. The proposed model and associated findings provide valuable insights for designing an effective matching system and incentive scheme for carpooling services in practice.
Article
Buses operating in mixed traffic experience problems with delay and travel time variability in peak periods. Numerous transit priority measures are found in the literature but most rely on separating buses from other vehicles. Complete separation such as dedicated bus lanes might underutilize the system capacity when the frequency of buses is not high. We propose a “dynamic bus lane policy”, where control adjusts the proportion of cars to buses in one lane of a multi-lane arterial instead of enforcing complete separation of vehicle types. This strategy is analyzed with aggregated macroscopic dynamics for different models of lane choice. It is shown to benefit both cars and buses by maintaining higher outflow during the peak period and helping the system to recover more quickly at the end of the peak. Greater reductions in travel time are possible with increased information available to vehicles. Analytical derivations and non-linear optimization are then used to obtain the system optimal allocation of cars, as well as the toll needed to achieve it. The system optimal tolling would be difficult to implement in practice. Another optimization which includes tolls paid in its objective is nearly as good at reducing vehicle hours traveled and produces a much simpler pricing structure amenable to feedback control. A microsimulation with feedback control confirms the results of the macroscopic model and shows additional benefits attributable to driver behavior. Future work will look into varying control parameters to achieve a global minimum travel time and will incorporate user heterogeneity to test pricing strategies.
Conference Paper
The use of the HOV lane in a city is an effective way to alleviate traffic pressure, solve traffic congestion, and meet people’s travel needs. Studying the implementation effect of HOV lane is of great significance for the humanized management of urban traffic. Through collecting Shenzhen traffic data, the traffic flow parameters of HOV lane was investigated. According the actual operation of Shenzhen HOV lane, VISSIM was selected as the simulation software. Through establishing the HOV characteristic evaluation index system, multiple points of data are collected. The analysis and evaluation results show that the Binhai Avenue HOV lane helps reduce flow and delays, increasing the average speed, service level, and the number of transported vehicles. This provides a reference for the Shenzhen traffic management bureau to improve transportation efficiency.
Article
Intense lane-changing maneuvers at weaving sections often cause traffic turbulence on expressways, especially in the presence of a concurrent medium exclusive bus lane (XBL) and general purpose lanes. Such intense lane-changing activity usually affects the operation and reduces the capacity of weaving sections in relation to their equivalent basic expressway segments. In this context, a study on the capacity model of weaving areas on an expressway with a median XBL is conducted based on the analysis of lane-change behaviors using gap acceptance theory. Two weaving sections on expressways with median XBL are selected as case studies to obtain the estimated capacity as well as the maximum traffic throughput under a certain bus saturation on the XBL. The results show that estimated capacity is larger than maximum traffic throughput because of low utilization rate of buses on the XBL, and capacity is significantly affected by weaving demand. Error measures based on the estimated and observed maximum traffic throughput are analyzed to verify the validity of the proposed model. A sensitivity analysis shows that, compared with the increase of on-ramp bus flow ratio, the increase of off-ramp bus flow ratio results in a more obvious trend of the reduction of capacity and maximum traffic throughput.
Article
Full-text available
Maximum throughput occurs between 50 and 70 mph in 85 percent of all 3,363 loop detectors in Los Angeles and Ventura Counties (Caltrans District 7). Of these, at 112'slow'detectors maximum throughput is reached at speeds below 40 mph. All but one slow detector is located in the outer lanes. Except for 25 locations, the speed at these 112 slow detectors exceeds 50 mph when the flow aggregated across all lanes at those locations is maximized. Thus traffic below free flow speed (nominally 60 mph) must result in inefficient operation of LA freeways and unnecessary traveler delay. The study is based on 5-minute averages of data from all loops on September 1, 2000, from midnight to noon, covering the morning peak period.
Article
This paper deals with life cycle benefit-cost analysis of a system, which has both repairable failures and non-repairable failures. The analysis involves the rewards generated by the system, the construction cost of the system, the inspection cost, the repair cost and the disposal cost during the life-time of the system. By using probability analysis, the supplementary variable technique, definite integral and the Laplace transform, this paper obtains the total profit function and the profit rate function based on the life cycle of the system. As an application of the profit rate function, the optimal inspection policy of the system is also studied.
Article
The California Freeway Performance Measurement System stores real-time data from 26,000 loop detectors. PeMS is accessed via an internet browser (http://pems.eecs.berkeley.edu/). It currently has 3 TB of data, growing at 2 GB/day. PeMS extracts useful information from these data and displays it in graphical or tabular form. These data provide an unparalled opportunity to assess freeway performance and suggest ways to improve freeway management. The paper illustrates this opportunity using six studies of freeway congestion, ranging from bottleneck identification to HOV lane effectiveness. The paper is not a contribution to theory, but it may encourage theoreticians to use a rich data set to formulate and address practical questions.
Article
A travel time prediction algorithm scalable to large freeway networks with many nodes with arbitrary travel routes is proposed. Instead of constructing separate predictors for individual routes, it first predicts the whole future space-time field of travel times and then traverses the required subsection of the predicted travel time field to compute the travel time estimate for the requested route. Compared with the traditional approach that offers the same flexibility, the proposed method substantially reduces storage and computation time requirements at the relatively small computational cost at the time of actual prediction. It is first established that travel times computed by traversing travel time fields are compatible with more direct measurements of travel tunes from a vehicle reidentification technique based on electronic toll collection tags. This provides a conceptual justification of the proposed approach. When applied to the loop data from an 8.7-mi section of the 1-80 freeway, the proposed approach with a time-varying coefficient (TVC) linear regression model as the component predictor not only improves the baseline historical travel time predictor substantially, with a 40% to 60% reduction in the prediction error, but also improves the traditional whole-route predictor based on the same TVC regression model by 6% to 9%. The result suggests that the proposed algorithm not only achieves the scalability but also improves prediction accuracy, both of which are critical for successful deployment of the advanced traveler information system for large freeway networks.
Article
Single-loop detectors provide the most abundant source of traffic data in California, but loop data samples are often missing or invalid. A method is described that detects bad data samples and imputes missing or bad samples to form a complete grid of clean data, in real time. The diagnostics algorithm and the imputation algorithm that implement this method are operational on 14,871 loops in six districts of the California Department of Transportation. The diagnostics algorithm detects bad (malfunctioning) single-loop detectors from their volume and occupancy measurements. Its novelty is its use of time series of many samples, instead of basing decisions on single samples, as in previous approaches. The imputation algorithm models the relationship between neighboring loops as linear and uses linear regression to estimate the value of missing or bad samples. This gives a better estimate than previous methods because it uses historical data to learn how pairs of neighboring loops behave. Detection of bad loops and imputation of loop data are important because they allow algorithms that use loop data to perform analysis without requiring them to compensate for missing or incorrect data samples.
Max. flow in D12 occurs at 60mph
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HOV Lane Operation and the Impact of Introducing Hybrids Vehicles to HOV lanes in California. Draft final report prepared for California Department of Transportation
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The Road to Hell is Clogged with Righteous Hybrids
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Evaluate Effectiveness of High Occupancy Vehicle (HOV) Lanes, Utah Department of Transportation
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HOV Enforcement Task Force Makes Recommendations To Safeguard HOV lanes
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HOV actuation at the same time all along an HOV lane creates a huge congestion 458 in the GP lanes (visible in Fig. 10). A much better approach may be to stagger actuation times to minimize this 459 'shoulder' effect
  • In Second
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  • Area
Second, in the Bay Area, HOV actuation at the same time all along an HOV lane creates a huge congestion 458 in the GP lanes (visible in Fig. 10). A much better approach may be to stagger actuation times to minimize this 459 'shoulder' effect. Such an approach needs investigation.
the average vehicle occupancy (AVO) values are 1.1 for GP and 2.1 for HOV vs. 1.2 for the 368 all GP lane freeway. We show later that
  • Operation
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Operation. Lastly, the average vehicle occupancy (AVO) values are 1.1 for GP and 2.1 for HOV vs. 1.2 for the 368 all GP lane freeway. We show later that, based on San Francisco Bay Area data, the assumed values are 369 defensible.
525 Freeway Performance Measurement System (PeMS)
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The Hybrid's Free Ride
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Efficient Operation increases person and vehicle throughput by 10%, compared with Inefficient 378
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Second, Efficient Operation increases person and vehicle throughput by 10%, compared with Inefficient 378
California Statewide Household Travel Survey. 507 California Department of Transportation (Caltrans), District 4
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HOV lanes in the Bay Area
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Inefficient Operation' allows traffic to become congested lowering speed to 30 mph in a GP 363 lane but maintains 45 mph in the HOV lane
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HOV lane; 'Inefficient Operation' allows traffic to become congested lowering speed to 30 mph in a GP 363 lane but maintains 45 mph in the HOV lane.
California Life-Cycle Benefit/Cost Analysis Model
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High Occupancy Vehicle (HOV) Lane Master Plan Update. Prepared for Metropolitan Transportation Commission, Caltrans District 4 and the California Highway Patrol Golden Gate Division
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Report submitted to the California Air Resources Board and the California Department of Transportation
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HOV Performance Program Evaluation Report. Prepared for Los Angeles County Metropolitan Transportation Authority
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