Wanjing Ma

Tongji University · Key Laboratory of Road and Traffic Engineering of the State Ministry of Education

Through and right-turn shared lanes are widely designed to increase the capacity of through traffic, but they can also cause delays for right-turn vehicles. This study presents a dynamic control method for a shared lane that prioritizes right-turn vehicles at the beginning of the cycle and subsequently allows through traffic to queue in the shared...

As an emerging data source, the trajectories of probe vehicles can compensate for the deficiencies of high maintenance costs and low coverage ranges of infrastructure-based detectors (e.g., loop detectors). However, existing arterial signal coordination studies typically assume high-penetration-rate trajectories, which are difficult to achieve in r...

Existing trajectory-based signal timing studies either assume time-invariant vehicle arrivals or require high penetration rates of connected vehicles (CVs). However, vehicle arrivals at an urban intersection typically follow a cyclic pattern in the real world due to the impacts of traffic signals at upstream signalized intersections. And the penetr...

This paper presents an integrated optimal controller for the tandem intersection with lane function design and signal control, aiming to improve intersection efficiency and service reliability with a multi-objective formulation. The tandem intersection is a type of unconventional intersection that can re-organize the vehicles at entrance lanes with...

Intersection channelization and signal timing are important for mitigating traffic congestion in the urban transportation system. Most existing studies fail to quantitively evaluate the severity of deadlock caused by the mismatch between lane allocation and signal timing, especially at a channelized intersection with auxiliary lanes. This study pro...

Sparse trajectory data with non-second-by-second sampling intervals are common. However, most carbon emission estimation models for vehicles require second-by-second inputs. Additionally, some models ignore the emission generation principle, and some have complicated inputs. To address these limitations, this study proposes a vehicle carbon emissio...

Traffic conflict prediction is one of the important principles in Advanced Driving Assistance System (ADAS). Previous research mainly focuses on calculating the risk of conflicts with surrogate safety measures, while the prediction of driver's rear-end risk avoidance behavior after conflict is less considered. Therefore, this study intended to pred...

With the development of the cooperative vehicle and infrastructure systems (CVIS), trajectory planning for Connected Autonomous Vehicles (CAVs) provides a promising solution to the management of merging vehicles at a freeway on-ramp. Existing studies mainly focus on the planning of trajectory profiles or trajectory points at each time step assuming...

Queue length is one of the most commonly used indicators to evaluate traffic operation at signalized intersections. Many studies aim to estimate queue length using trajectory data, but this remains a challenge with spatially sparse trajectories. This paper introduces a probabilistic-based method for cycle-by-cycle estimation of queue length distrib...

In-lane street hawking remains one of the urbanization challenges emanating from unemployment in sub-Saharan Africa. Although forceful evictions have been largely unsuccessful, the possibility of finding alternative livelihood sources for hawkers to relocate them from the road network has received little attention in the literature. Using secondary...

Efficient traffic control can alleviate traffic congestion, reduce fuel consumption, and improve traffic safety. With the development of communication and automation technologies, regular vehicles (RVs), connected vehicles (CVs), and connected and automated vehicles (CAVs) will coexist on urban roads in the near future. In this paper, we systematic...

With the development of internet of vehicles and automated driving, individual-based trajectory control at intersections becomes possible. Trajectory planning and coordination for connected and automated vehicles (CAVs) have been studied at isolated “signal-free” intersections and in “signal-free” corridors under the fully CAV environment in the li...

The study of expressway rear-end conflicts is of great significance to analyze driving behaviors and improve traffic safety. However, research on the classification and modeling of conflict patterns is still lacking. This study aimed to explore conflict patterns and their relationship with influencing factors. The conflict data used in this study w...

It is widely accepted that an unintended lateral attack is inevitable in the intelligent connected vehicle environment. This paper explores the feasibility of a reinforcement learning method named PPO (Proximal Policy Optimization) to handle the unintended lateral attack and keep the vehicle stay in the ego lane. Based on the China highway design g...

Public bike-sharing is common in many regions, but rare in sub-Saharan Africa. Despite the myriad of advantages, only five African countries have implemented it. Besides, road user perceptions of novel bike-sharing implementation remain underrepresented in the extant literature. The lack of data in sub-Saharan Africa makes planning and implementati...

Accurate estimation of route flow is crucial to traffic control optimization. Existing route flow estimation models are typically built upon strong assumptions on traveler route choice behavior or turn to data-driven approaches which heavily rely on prior OD estimation and high sensor coverage rate. This study proposes a route flow estimation frame...

Traffic state information is critical for drivers’ route choice and traffic management, numerous studies targeted on traffic state evaluation for expressways exist. Few studies have conducted traffic state prediction for expressways, and the congestion mechanism has not been explored comprehensively. This study aims to conduct traffic state predict...

Pedestrian deaths constitute 23% of road traffic deaths globally. Although several research papers have contributed to pedestrian safety analysis, they did not provide a comprehensive overview of the progress in the research domain and publication trends. This makes it difficult to identify trends and insights into the pedestrian research domain...

The proportion of rear-end crashes is the highest for expressways. An effective ways to reduce the rear-end crash risk is Active Traffic Management (ATM), and knowing the mechanism of how contributing factors affect crash risk in space and time is the foundation of ATM. However, the existing studies are mainly based on highly aggregated traffic dat...

The demand for motorcycle taxis has seen a significant increase in Ghana in the last decade. In light of an existing unimplemented ban, several questions arise on the prospects of strong formal regulation and policy implementation. However, the lack of succinct research data on motorcycle taxi regulation from users' perspectives leaves a gap in pol...

Signalized intersections require regular safety and performance audits because of their high user demands. Most of the crashes on urban roads are attributed to the condition of signalized intersections. Some typical audit variables comprise vehicle crashes, road markings, signal control, pedestrian-vehicle movements, the composition of the flows, a...

Shuttle bus services play a vital role in public transit systems. However, conventional shuttle bus systems use the same type of buses and fixed departure timetables. They fail to meet the time-varying travel demand and do not consider the diversified characteristics of transit passengers. With the advent of the information era, communication among...

It is commonly seen that buses are blocked by the ones in front serving passengers and have to queue outside a curbside bus stop although there are vacant berths at the stop. The resultant bus delays degrade the service level of urban public transportation. A potential solution is to reschedule the arrivals of the buses at the stop for full utiliza...

Mixed traffic control with connected and autonomous vehicles (CAVs) and human driving vehicles (HVs) is becoming a hot topic. CAV trajectory planning at work zones under the mixed traffic environment is a big challenge. Existing studies only focus on longitudinal trajectories (e.g., acceleration profiles), ignoring lateral trajectories (lane changi...

Due to the manoeuvre complexity, models describing the platoon formation process on urban roads are lacking in the literature. Inspired by flocking behaviours in nature, we proposed a two-dimensional model to describe connected automated vehicle (CAV) group dynamics based on the potential theory, which is composed of the elastic potential energy fo...

Pricing directly affects the sustainable development of the flexible bus service. This study proposes a profit maximization model and a social welfare maximization model for the flexible bus operator based on the cumulative prospect theory. Fares and uncertain travel time due to unforeseen detours in serving passengers jointly affect passengers’ mo...

Connected and automated vehicles (CAVs) and human-driven vehicles (HVs) are expected to coexist in the near future. CAV-dedicated lanes and phases have been explored to handle the uncertainty in the driving behavior of HVs in the mixed traffic environment. However, CAV-dedicated phases could significantly sacrifice HV benefits. This study proposes...

Different human-machine collaboration modes and driving simulation tests with the orthogonal method considered are designed for a series of typical intelligent highway landscapes. The feedback of drivers under different interaction modes is evaluated through NASA-LTX questionnaire, driving simulator, eye tracker, and electroencephalograph (EEG). Th...

Public transit systems play an important role in the alleviation of traffic congestion in urban road networks. The same vehicle type and a fixed departure timetable are usually applied to a bus route in the conventional public transit systems. They fail to cater to the time-varying travel demand or the diversified characteristics of transit passeng...

The surge of connected and autonomous vehicles has aroused rising attention from both academia and industrial world. In this context, this article introduces recent new applications concerning traffic control and how those traditional applications can be subverted by the emergence of those new-type vehicles. This article summarizes relevant study m...

Traffic flow forecasting is an important issue for traffic planning, design and management. In this study, we propose a multimodal deep learning approach for short-term traffic flow forecasting, which can jointly and adaptively learn the variation regulation of long temporal trend, seasonality, and residual of traffic flow produced by multi-dimensi...

Active traffic management (ATM) strategies are useful methods to reduce crash risk and improve safety on expressways. Although there are some studies on ATM strategies, few studies take the moving vehicle group as the object of analysis. Based on the crash risk prediction of moving vehicle groups in a connected vehicle (CV) environment, this study...

Introduction: Studies have proven that the crash possibility and crash type are not the same among different expressway segment types. However, few studies have conducted real-time safety analysis considering different segment types. This study aimed to explore the crash mechanism's heterogeneity for different segment types (i.e., merge, diverge,...

The bus transit system is promising to enable electric and autonomous vehicles for massive urban mobility, which relies on high-level automation and efficient resource management. Besides the on-road automation, the in-depot automated scheduling for battery recharging has not been adequately studied yet. This paper presents an integrated in-depot r...

Abstract Roundabouts promise potential safety and efficiency benefits in the homogenous environment of conventional vehicles. However, their performance can deteriorate if high and/or imbalanced traffic exists. The advent of connected and automated vehicles (CAVs) has provided great opportunities to make transportation infrastructures more efficien...

It is commonly seen that buses are blocked by the ones in front serving passengers and have to queue outside a curbside bus stop although there are vacant berths at the stop. The resultant bus delays degrade the service level of urban public transportation. A potential solution is to reschedule the arrivals of the buses at the stop for full utiliza...

One-way carsharing system has been widely adopted in the carsharing field due to its flexible services. However, as one of the main limitations of the one-way carsharing system, the imbalance between supply and demand needs to be solved. Predicting pick-up demand has been studied to achieve the goal, but using returned vehicles to reduce unnecessar...

Connected and automated vehicles (CAVs) and human-driven vehicles (HVs) are expected to coexist in the near future. CAV-dedicated lanes and phases have been explored to handle the uncertainty in the driving behavior of HVs in the mixed traffic environment. However, CAV-dedicated phases could significantly sacrifice HV benefits. This study proposes...

One-way carsharing is an alternative shared-use transportation mode that provides flexible travel accommodations for urban mobility. However, vehicle distributions can be mismatched with demand distributions because users are not required to return to their departure locations. Conventional operator-based vehicle relocation is limited by labor reso...

The Signal Phase and Timing (SPaT) message is an important input for research and applications of Connected Vehicles (CVs). However, the actuated signal controllers are not able to directly give the SPaT information since the SPaT is influenced by both signal control logic and real-time traffic demand. This study elaborates an estimation method whi...

Existing fixed-time traffic signal optimization methods mainly use traffic volumes collected by infrastructure-based detectors (e.g., loop detectors). These infrastructure-based detectors generally have high maintenance costs and low coverage. With the deployment of probe vehicles, vehicle trajectory data provide more information about traffic stat...

Fixed-time signal control is widely used in the real world due to its low cost of implementation. Repeated signal cycles with the same phase structure are applied in the existing fixed-time signal control schemes. However, such signal schemes do not always achieve the best performance, especially when traffic demand is unbalanced. The inclusion of...

Trajectory planning and coordination for connected and automated vehicles (CAVs) have been studied at isolated ``signal-free'' intersections and in ``signal-free'' corridors under the fully CAV environment in the literature. Most of the existing studies are based on the definition of approaching and exit lanes. The route a vehicle takes to pass thr...

Urban traffic congestion has an obvious spatial and temporal relationship and is relevant to real traffic conditions. Traffic speed is a significant parameter for reflecting congestion of road networks, which is feasible to predict. Traditional traffic forecasting methods have poor accuracy for complex urban road networks, and do not take into acco...

Variable speed limit (VSL) system has been recognised as an active traffic management strategy to improve traffic safety and operational efficiency. The development of connected vehicle (CV) technologies have a potential to improve VSL systems because CVs can provide continuous and precise traffic condition as the input of VSL algorithm as well as...

A lane-based optimization model for lane function and signal phase at intersection was established， considering the interaction of complex factors such as different approaches，different flow directions，different lane functions and different phase schemes. The objective function of the model was to minimize the critical flow ratio of the intersectio...

This paper presents an integrated optimization model for the concurrent design of passive bus priority signal settings and lane allocation including lane markings for general traffic and exclusive bus lanes at isolated intersections. Traditional passive transit signal priority (TSP) strategies considered both lane markings for general traffic and e...

The one-way carsharing system has been widely used in the carsharing field due to its flexibility. However, one of its main disadvantages is the imbalance between supply and pickup demand. At present, multi-source data are available for the real-time prediction of pickup demand. The multi-source data that are used for this purpose include real-time...

This paper presents an integrated optimization model for the concurrent design of passive bus priority signal settings and lane allocation including lane markings for general traffic and exclusive bus lanes at isolated intersections. Traditional passive transit signal priority (TSP) strategies considered both lane markings for general traffic and e...

With the looming promise of wireless recharging technology, electric vehicles (EVs) are going to be able to acquire energy while still in motion. This paper focuses on the optimal deployment of wireless recharging facilities on signalized arterials for EVs. To address this issue, a bi-objective model considering both traffic operation efficiency (i...

Trajectory planning for connected and automated vehicles (CAVs) has been studied at both isolated intersections and multiple intersections under the fully CAV environment in the literature. However, most of the existing studies only model limited interactions of vehicle trajectories at the microscopic level, without considering the coordination bet...

The head-up display (HUD) is a display device which projects a virtual image on the forward field of view of drivers. It was first developed for military aviation then started to be applied for cars. Great progresses have been made to HUD in research and practice. A good summary of the current work regarding HUD will facilitate its future applicati...

With the development of connected vehicle (CV) technology, more and more algorithms for improving the control efficiency of intersections have been proposed. However, most of these control algorithms were proposed under the environment of fully connected autonomous vehicles (CAVs). Seldom CV or CAV related studies have been conducted for all-way-st...

Traffic congestion causes traveler delay, environmental deterioration, and economic loss. Most studies on congestion mitigation focus on attracting travelers to public transportation and expanding road capacity. Few studies have been found to analyze the contribution of different traffic flows to the congestion on roads of interest. This study prop...

The time-of-day (TOD) mode is the most widely used strategy for traffic signal control with fluctuating flows. Most studies determine TOD breakpoints based on traffic volumes collected by infrastructure-based detectors (e.g., loop detectors). However, these infrastructure-based detectors have low coverage and high maintenance cost. With the deploym...

One-way carsharing has been regarded as one of the innovative urban transportation modes since the last decade. A fleet imbalance problem frequently occurs in the system, which requires efficient vehicle relocation to cope with. An incentive-based approach could influence the users’ demands and could relieve the pressure on operator-based relocatio...

This is a poster presented on TRB 98th annual meeting.

The stop-controlled intersection is widely used all over the world. However, owing to the regional differences in driving behavior, its performance varies geographically. This study analyzed the stop behavior and critical gap using field data collected at 14 two-way stop-controlled intersections in Shanghai, China. A logistic model was established...

Arterial traffic signal coordination makes traffic flow more efficient and safer. This paper presents a partition-enabled multi-mode band (PM-BAND) model that is designed to solve the signal coordination problem for arterials with multiple modes, i.e., passenger cars and transit vehicles. The proposed method permits the progression bands to be brok...

On-demand one-way carsharing systems are increasingly gaining popularity nowadays and the market is growing unprecedentedly. However, operating techniques such as vehicle surveillance and fleet management fall behind the industrial development. Practice on EVCARD – an on-demand one-way electric vehicle carsharing system operating in Shanghai – rais...

Vehicle unbalance usually occurs in multistation electric carsharing systems. Threshold triggering method is one of the most practicable approaches for vehicle relocation, while determination of thresholds has not been sufficiently studied particularly for electric carsharing system. This paper presents an approach on determining the thresholds con...

The construction of exclusive bus lanes is a strategy for giving priority to buses and improving the efficiency of the urban transportation system, and for that purpose, center transit lanes are an important type of transit lane. Along the center transit lanes, the operation of intersections with bus stops becomes more complex because there are fou...

Existing traffic signal control systems only allocate green time to different phases to avoid conflicting vehicle movements. With advances in connected and automated vehicle (CAV) technologies, CAV trajectories not only provide more information than existing infrastructure-based detection systems, but also can be controlled to further improve mobil...

As a typical safety-critical cyber-physical system, the brake-by-wire system, which provides improved control and enhanced performance, shows promise as an automotive braking scheme. In addition, the BBW system can be incorporated into all types of vehicles, including conventional vehicle with an internal combustion engine, electrified vehicles, an...

Parclo (partial cloverleaf) interchange, connecting major freeways and surface streets with one or two loop ramps and two closely spaced intersections, is one of the most commonly used interchange types in urban and suburban areas. The two-ramp terminal intersections are often the critical bottlenecks for the parclo interchange system, especially w...