Yafeng Yin

University of Michigan | U-M · Department of Civil and Environmental Engineering

On-demand delivery services are three-sided markets that enable interactions between customers and suppliers with the help of crowdsourced drivers. Customers and suppliers may pay a commission to gain access to the service and drivers are granted a wage for providing their delivery service. This study characterizes the properties of three-side on-d...

Ride-pooling, which accommodates multiple passenger requests in a single trip, has the potential to substantially enhance the throughput of mobility-on-demand (MoD) systems. This paper investigates MoD systems that operate mixed fleets composed of “basic supply” and “augmented supply” vehicles. When the basic supply is insufficient to satisfy deman...

Emerging on-demand service platforms (OSPs) have recently embraced teamwork as a strategy for stimulating workers’ productivity and mediating temporal supply and demand imbalances. This research investigates the team contest scheme design problem considering work schedules. Introducing teams on OSPs creates a hierarchical single-leader multi-follow...

The entry of transportation network companies like Uber and Lyft in the ride-hailing market has generated concerns that they unfairly compete against traditional street-hail services. However, regulatory action seeking to address this issue has either been lacking or has resulted in the suspension or restriction of e-hail services. In this paper, w...

The current approach to driving automation has been primarily vehicle-centric. However, a vehicle-infrastructure cooperative approach, in which infrastructure and vehicles cooperate to perform the different driving tasks, may prevail in enabling automated driving. This paper conducts an economic analysis of vehicle infrastructure cooperation for au...

This study examines regulatory policies for electrifying a ridesourcing system. To do so, we develop an aggregate modeling framework to analyze a ridesourcing market involving electric vehicles and examine the response of the ridesourcing platform to regulatory policies such as annual permit fees (AP), differential trip-based fees (TB) or different...

On-demand ride-hailing services are becoming a ubiquitous means of mobility in major cities. While convenient and accessible, they are costly for many, and thus ride-hailing providers are often offering pooling options that allow passengers to share a ride and split the fare. The downside of pooling is the extra waiting time passengers may experien...

Connected automated vehicles (CAVs) use sensors to scan their surrounding environment in order to make safe and efficient motion decisions. The richness of a CAV's vision depends on the configuration of on-board sensors and the ability of CAVs to share data with nearby vehicles. High-end sensors provide quality data, allowing CAVs to rely on their...

This paper studies a multi-fleet platoon coordination system in transport networks that deploy hubs to form trucks into platoons. The trucks belong to different fleets that are interested in increasing their profits by platooning across fleets. The profit of each fleet incorporates platooning rewards and costs for waiting at hubs. Each truck has a...

This study considers dynamic parking management in the era of driving automation that users of privately-owned automated vehicles (AVs) come to a downtown area to conduct various activities and choose between three parking options: outskirt parking, on-street parking, and cruising-as-substitution-for-parking. In the latter, AVs cruise in downtown u...

A cooperative truck platoon is a set of virtually linked trucks driving with a small intra-vehicle headway enabled by connected and automated vehicle technologies. One of the primary benefits of truck platooning is energy savings due to the reduction of aerodynamic drag on the platooned vehicles. The focus of this paper is on scheduling travel itin...

Cooperative vehicle platooning enabled by connected automated vehicle (CAV) technology has shown to bring various benefits including energy savings and a reduction in driving effort. Nevertheless, because these benefits vary over different platoon positions, vehicles from different owners may not be willing to platoon together; even if they form a...

Ride-sourcing services play an increasingly important role in meeting mobility needs in many metropolitan areas. Yet, aside from delivering passengers from their origins to destinations, ride-sourcing vehicles generate a significant number of vacant trips from the end of one customer delivery trip to the start of the next. These vacant trips create...

Ride-sourcing services have experienced dramatic growth over the past decade but aroused debates on whether and how the government should regulate the ride-sourcing platform. To tackle this critical issue, this paper investigates the regulatory outcomes of various representative government regulations, including price-cap regulation, vehicle fleet...

Ride-sourcing drivers spend a significant portion of their service time being idle, during which they can move freely to search for the next customer. Such customer-searching movements, while not being directly controlled by ride-sourcing platforms, impose great impacts on the service efficiency of ride-sourcing systems and thus need to be better u...

Truck platooning enabled by connected automated vehicle (CAV) technology has been demonstrated to effectively reduce fuel consumption for trucks in a platoon. However, given the limited number of trucks in the traffic stream, it remains questionable how great an energy saving it may yield for a practical freight system if we only rely on ad-hoc pla...

Matching trip requests and available drivers efficiently is considered a central operational problem for ride-hailing services. A widely adopted matching strategy is to accumulate a batch of potential passenger-driver matches and solve bipartite matching problems repeatedly. The efficiency of matching can be improved substantially if the matching i...

This paper proposes a macroscopic fluid modeling framework to assist with strategic decision making of a platform for operating a large-scale on-demand app-based ride-hailing system. The framework captures the spatiotemporal characteristics of a ride-hailing system, and is flexible in representing control policies that a platform is implementing. I...

This paper proposes a model of the ridesourcing market in presence of traffic congestion and with the provision of both solo and pooling services. Our analysis of the first-best solution shows that, under a highly congested scenario, the ridesourcing platform may enjoy non-negative profits. However, when congestion is low, the ridesourcing market m...

Matching trip requests and available drivers efficiently is considered a central operational problem for ride-hailing platforms. A widely adopted matching strategy is to accumulate a batch of potential passenger-driver matches and solve bipartite matching problems repeatedly. The efficiency of matching can be improved substantially if the matching...

Automated vehicles (AVs) eliminate the burden of finding a parking spot upon arrival to the destination, because they can park at a strategic location or cruise until summoned by their users. In this study, we investigate the parking choices of privately-owned AVs in a downtown area. Since each user’s choice has impacts on another via cruising-incu...

To cope with the uncertainty of labor supply from freelance/self-scheduling drivers, some ride-sourcing platforms recruit contractual drivers, who are paid a fixed salary for pre-specified work schedules. This paper develops an aggregate modeling framework to examine the practicability of such a dual-sourcing strategy. We investigate the optimal co...

This paper investigates intersection control in a fully connected and automated vehicles (CAV) environment, which aims to coordinate in real-time conflicting traffic movements under safety and kinodynamic constraints to maximize intersection throughput or minimize traffic delay. Given the problem’s NP-hardness, we leverage graph coloring to devise...

As a consequence of the sharing economy attaining more popularity, there has been a shift toward shared-use mobility services in recent years, especially those that encourage users to share their personal vehicles with others. To date, different variants of these services have been proposed that call for different settings and give rise to differen...

Matching trip requests and available drivers efficiently is deemed a central operational problem for ride-hailing platforms. A widely-adopted matching strategy is to formulate and solve bipartite matching problems repeatedly. The efficiency of matching can be improved substantially if the matching time interval is adaptively changed. The optimal ti...

In this paper, we study the Minimum Weight Pairwise Distance Preservers (MWPDP) problem. Consider a positively weighted undirected/directed connected graph $G = (V, E, c)$ and a subset $P$ of pairs of vertices, also called demand pairs. A subgraph $G'$ is a distance preserver with respect to $P$ if and only if every pair $(u, w) \in P$ satisfies $d...

The work scheduling flexibility enjoyed by drivers of ride-sourcing platforms poses challenges for these platforms in effectively managing their workforce. A key to resolving these challenges is to understand how drivers set up their work schedule so as to inform management decisions. This letter summarizes our investigation of ride-sourcing driver...

This paper aims to synchronize timetables in a transit network so as to minimize the total passenger transfer waiting time. Assuming a fixed headway for each line, we first formulate the problem as an optimization problem with congruence constraints. We show that the problem is NP-hard, and investigate several special cases of the problem that are...

This paper develops a novel parking navigation system for downtown parking that aims to mitigate parking competition by guiding drivers to appropriate vacant parking spaces. Given drivers’ real-time locations and their parking preferences, a two-sided matching algorithm is firstly adopted to achieve a stable driver-optimal matching, under which dri...

Ride-sourcing services play an increasingly important role in meeting mobility needs in many metropolitan areas. Yet aside from delivering passengers from their origins to destinations, ride-sourcing vehicles generate a significant number of vacant trips from the end of one customer delivery trip to the start of the next. These vacant trips create...

Recently, the employment of different types of incentives in transportation systems to form advanced transportation congestion management solutions has garnered significant attention. Instead of using presumed or fixed-amount incentives, this paper develops an integrated and personalized traveler information and incentive scheme to incentivize towa...

This paper studies the supply curve of ride-hailing systems under different market conditions. The curve defines a relationship between the throughput of trips of the system and the cost of riders it serves. We first focus on isotropic markets by revisiting a matching failure identified recently that matches a requesting rider with an idle driver v...

Recently, the employment of different types of incentives in transportation systems to form advanced transportation congestion management solutions has garnered significant attention. Instead of using presumed or fixed-amount incentives, this paper develops an integrated and personalized traveler information and incentive scheme to incentivize towa...

This paper studies the supply curve of ride-hailing systems under different market conditions. The curve defines a relationship between the throughput of trips of the system and the cost of riders it serves. We first focus on isotropic markets by revisiting a matching failure identified recently that matches a requesting rider with an idle driver v...

A cooperative truck platoon is a set of virtually linked trucks driving with a small intra-vehicle gap enabled by connected and automated vehicle technologies. One of the primary benefits of truck platooning is energy savings due to the reduction of aerodynamic drag on the platooned vehicles. The focus of this paper is on scheduling travel itinerar...

In this paper, a decentralized traffic signal control strategy named max pressure control is reviewed and examined. This control strategy aims at optimizing overall network throughputs, but applies a distributed approach that only requires local information to generate timing plans for each intersection. A Vissim simulation study is conducted to co...

This paper introduces a framework for the design and deployment of safety service patrols (SSP) on freeways. Three mathematical programming models are proposed, with the targets of minimizing fleet size and total average response time and maximizing social benefits to accommodate various design objectives. Fast heuristic algorithms based on neighbo...

The time limited-parking management plan has been widely adopted in curbside parking and in terminal parking. This plan separates parking spaces into several parking groups and manages each group with a specific duration limit. By doing so, the turnover rates and the availability of convenient parking resources are increased. In this paper, a bilev...

This paper develops a model to investigate the effects of spatial pricing on ride-sourcing markets. The model is built upon a discrete time geometric matching framework that matches customers with drivers nearby. We demonstrate that a customer may be matched to a distant vehicle when demand surges, yielding an inefficient supply state. We further i...

This study proposes equilibrium models under different behavioral assumptions of labor supply in a ride-sourcing market and then investigates the performance of surge pricing. A time-expanded network is first proposed to delineate possible work schedules of drivers. Based on the proposed network, we provide formulations and algorithms for both neoc...

Ride-sourcing services have become increasingly important in meeting travel needs in metropolitan areas. However, the cruising of vacant ride-sourcing vehicles generates additional traffic demand that may worsen traffic conditions. This paper investigates the allocation of a certain portion of road space to on-street parking for vacant ride-sourcin...

This study proposes equilibrium models under different behavioral assumptions of labor supply in a ride-sourcing market and then investigates the performance of surge pricing. A time-expanded network is first proposed to delineate possible work schedules of drivers. Based on the proposed network, we provide formulations and algorithms for both neoc...

In this study a framework is proposed for minimizing the societal cost of replacing gas-powered household passenger cars with battery electric ones (BEVs). The societal cost consists of operational costs of heterogeneous driving patterns' cars, the government investments for charging deployment, and monetized environmental externalities. The optimi...

In this study we explore two charging management schemes for plug-in hybrid electric vehicles (PHEVs). The PHEV drivers and the government are stakeholders who might prefer different charging control strategies. For the former, we propose a controlled charging scheme that minimizes the operational cost during PHEV charge-depleting and sustaining mo...

This paper proposes a route choice model that incorporates the various behavioral mechanisms in route choice proposed in the literature including the shortest path, bounded rationality, asymmetric preference, and the time surplus maximization. In the proposed model, travelers are assumed to compare travel cost to their status quo (travel cost of th...

This paper develops and analyzes a multiclass traffic assignment model considering the flow-dependent passenger car equivalent (PCE) value of trucks based on the latest Highway Capacity Manual (HCM, 6th edition) and explores the properties of the proposed model to provide guidance on related planning applications. HCM discrete values of truck PCEs...

This paper develops a model to investigate the effects of spatial pricing on ride-sourcing markets. The model is built upon a discrete time geometric matching framework that matches customers with drivers nearby. We demonstrate that a customer may be matched to a distant vehicle when demand surges, yielding an inefficient supply state. We further i...

This research had the objective of providing a decision support system for managers who must decide whether a roadway warrants the addition of a safety service patrol (SSP). Unlike the familiar signal warrants that guide the installation of traffic signals at candidate intersections, no such guidelines exist for decisions on SSPs. A proven framewor...

This paper advocates the need for infrastructure planning to adapt to and further promote the deployment of autonomous vehicle (AV) technology. It is envisioned that in the future government agencies will dedicate certain areas of road networks to AVs only to facilitate the formulation of vehicle platoons to improve throughput and hopefully improve...

Ride-sourcing refers to an emerging urban mobility service that private car owners drive their own vehicles to provide for-hire rides. This paper analyzes the ride-sourcing market using an aggregate model where the matchings between customers and drivers are captured by an exogenous matching function. It is found that without any regulatory interve...

The private provision of public roads via the build-operate-transfer (BOT) mode has been increasingly used around the world. By viewing a BOT contract as a combination of road capacity, toll and government guarantee, this paper investigates optimal concession contract design under both symmetric and asymmetric information about the marginal mainten...

This paper analyzes drivers’ search behavior for parking in a stylized setting where an attraction (destination) is located on a long one-way street and on-street parking spaces are scattered around the destination; drivers are assumed to find a parking space that minimizes their walking time to the destination. Analytical models were established t...

This paper proposes to use tradable credits to control the maximum queue length at a bottleneck. Given a queue length threshold specified by the traffic authority, the authors designed a tradable credit scheme to maintain the queue length of the bottleneck to be less than the threshold for homogenous travelers. The scheme was compared against a mul...

This paper explores how to optimally locate public charging stations for electric vehicles on a road network, considering drivers' spontaneous adjustments and interactions of travel and recharging decisions. The proposed approach captures the interdependency of different trips conducted by the same driver by examining the complete tour of the drive...

Instead of charging tolls on individual links, this paper considers doing the same on paths. Path and link tolls are “valid” if they encourage motorists to use routes that collectively lead to a target distribution, e.g., one that minimizes travel delay. Because the numbers of valid link and path tolls are typically infinite, an objective in pricin...

This paper studies the optimal multi-step toll design problem for the bottleneck model with general user heterogeneity. The design model is formulated as a mathematical program with equilibrium constraints (MPEC), which is NP-hard due to non-convexity in both the objective function and the feasible set. An analytical method is proposed to solve the...

This study determines the optimal electric driving range of plug-in hybrid electric vehicles (PHEVs) that minimizes the daily cost borne by the society when using this technology. An optimization framework is developed and applied to datasets representing the US market. Results indicate that the optimal range is 16. miles with an average social cos...

This paper examines the design and efficiency of a highway use reservation system where commuters need reservations to access a highway facility at specific times. We show that, by accommodating reservation requests to the level that the highway capacity allows, traffic congestion can be relieved. Generally, a more differentiated design of the rese...