Traffic Operations and Management

SPRINTER Rail: Grade Crossing/Traffic Signal Optimization Study

Wu, Guoyuan
Li, Irene
Zhang, Wei-Bin
Johnston, Scott
Li, Meng
Zhou, Kun
2009

The second phase of this project further investigates impacts to local traffic operations at intersections adjacent to signal preemption by SPRINTER commuter trains and comes up with countermeasures that not only minimize such impacts but also take into account the traffic signal coordination. An extended traffic signal optimization model has been developed to minimize overall traffic delays and the weighted width of “green band” along several coordinated traffic signals around the grade crossings. Based on the train’s movement detection at grade crossings and the waiting queue estimation...

Some Traffic Features at Freeway Bottlenecks

Cassidy, Michael J.
Bertini, Robert L.
1999

Observations from two freeway bottlenecks in and near Toronto, Canada indicate that the average rate vehicles discharge from a queue can be 10% lower than the flow measured prior to the queue's formation. Absent any influences from downstream, the queue discharge flows exhibited nearly stationary patterns that alternated between higher and lower rates. These alternating flow patterns were especially evident at one of the two sites, although the feature occurred at both sites during periods that immediately followed the onset of upstream queueing; i.e. a queue's formation was always...

PATH ATMIS State of the Research Annual Report Fiscal Year 1998/1999

Tam, Robert
1999

This report summarizes PATH ATMIS and Systems research for fiscal year 1998/1999. In each of the brief project descriptions we state the objectives of the project and outline its status and some of its principal results. These descriptions are not intended to be comprehensive or complete, but rather to present a picture of the main thrusts of each of the reported projects. References are provided in the end of the report for more detailed information about particular projects. Taken together, the collection of project descriptions should also give a reader an overview of the entire program...

PATH ATMIS State of the Research Annual Report Fiscal Year 1999/2000

Tam, Robert
2000

This report summarizes PATH ATMIS research for fiscal year 1999/2000. In each of the brief project descriptions we state the objectives of the project and outline its status and some of its principal results. These descriptions are not intended to be comprehensive or complete, but rather to present a picture of the main thrusts of each of the reported projects. References are provided in the end of the report for more detailed information about particular projects. Taken together, the collection of project descriptions should give the reader an overview of the entire ATMIS research program...

On the Impacts of Bus Stops Near Signalized Intersections: Models of Car and Bus Delays

Gu, Weihua
Gayah, Vikash V.
Cassidy, Michael J.
Saade, Nathalie
2014

Models are formulated to predict the added vehicle and person delays that can occur when a bus stop is located a short distance upstream or downstream of a signalized intersection. Included in the set of models are those that predict the expected delays that cars collectively incur when a bus blocks one of multiple lanes while loading and unloading passengers at the stop. Others in this set predict the expected added delays incurred by the bus due to car queues. Each model is consistent with the kinematic wave theory of highway traffic, as is confirmed through a battery of tests. And each...

Negative Externalities of GPS-Enabled Routing Applications: A Game Theoretical Approach

Thai, Jérôme
Laurent-Brouty, Nicolas
Bayen, Alexandre M.
2016

This work studies the impact of the increasing penetration of routing apps on road usage. Its conclusions apply both to manned vehicles in which human drivers follow app directions, and unmanned vehicles following shortest path algorithms. To address the problem caused by the increased usage of routing apps, we model two distinct classes of users, one having limited knowledge of low-capacity road links. This approach is in sharp contrast with some previous studies assuming that each user has full knowledge of the network and optimizes his/her own travel time. We show that the increased...

Integrating Traffic Velocity Data into Predictive Energy Management of Plug-in Hybrid Electric Vehicles

Sun, Chao
Sun, Fengchun
Hu, Xiaosong
Hedrick, J. Karl
Moura, Scott
2015

Recent advances in the traffic monitoring systems have made traffic velocity information accessible in real time. This paper proposes a supervised predictive energy management framework aiming to improve the fuel economy of a power-split plug-in hybrid electric vehicle (PHEV) by incorporating dynamic traffic feedback data. Compared with conventional model predictive control (MPC), an additional supervisory state of charge (SOC) planning level is constructed in this framework. A power balance PHEV model is developed for this upper level to rapidly generate optimal battery SOC trajectories,...

Achieving Higher Taxi Outflows from a Drop-off Lane: A Simulation-based Study

Yang, Fangyi
Gu. Weihua
Cassidy, Michael J.
Li, Xin
Li, Tiezhu
2020

Lanes used by taxis and other shared-ride vehicles at airports and rail terminals are often congested. The present paper examines congestion-mitigating strategies for a special type of lane inside of which taxis are prohibited from overtaking each other while dropping-off patrons. Taxis must therefore often wait in first-in-first-out (FIFO) queues that form in the lane during busy periods. Patrons may be discharged from taxis upon reaching a desired area near the terminal entrance. When wait times grow long, however, some taxis discharge their patrons in advance of that desired area. The...

Zero-Shot Autonomous Vehicle Policy Transfer: From Simulation to Real-World via Adversarial Learning

Chalaki, Behdad
Beaver, Logan E.
Remer, Ben
Jang, Kathy
Vinitsky, Eugene
Bayen, Alexandre
Malikopoulos, Andreas A.
2020

In this article, we demonstrate a zero-shot transfer of an autonomous driving policy from simulation to University of Delaware's scaled smart city with adversarial multi-agent reinforcement learning, in which an adversary attempts to decrease the net reward by perturbing both the inputs and outputs of the autonomous vehicles during training. We train the autonomous vehicles to coordinate with each other while crossing a roundabout in the presence of an adversary in simulation. The adversarial policy successfully reproduces the simulated behavior and incidentally outperforms, in terms of...

Introduction: Control Problems for Conservation Laws with Traffic Applications

Bayen, Alexandre
Monache, Maria Laura Delle
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
Bayen, Alexandre
2022

This book focuses on control problems for conservation laws, i.e., equations of the type: ∂tu+∂xf(u)=0ut+(f(u))x=0,$$\displaystyle \partial _t\, u + \partial _x\, f(u) = 0 \qquad u_t+(f(u))_x=0, $$where u:ℝ+×ℝ→ℝn$$u:\mathbb {R}^+\times \mathbb {R} \to \mathbb {R}^n$$is the vector of conserved quantities and f:ℝn→ℝn$$f:\mathbb {R}^n\to \mathbb {R}^n$$is the flux. Most results will be given for the scalar case (n = 1), but we will present few results valid in the general case.