Traffic Theory

Traffic Signal Plans to Decongest Street Grids

Sadek, Bassel
Doig Godier, Jean
Cassidy, Michael J.
Daganzo, Carlos F.
2022

Two new synchronization strategies are developed for signalized grids of two-directional streets. Both strategies are found to reduce congestion significantly more than do other approaches. One of the strategies is static and the other adaptive. Both use a common timing pattern for all signals on the grid but use a different offset for each. The static strategy serves the morning rush by providing perfect forward progression on all streets in the directions that point toward a reference intersection, one that is located near the center of gravity of all workplaces. For the evening rush,...

Placement and Management of Bus Bypass Segments in Dense, Congested Cities

Bronicki, Nadav
Doig, Jean C.
Cassidy, Michael J.
University of California Berkeley. Department of Civil and Environmental Engineering
2023

In this research, simulation is used to explore how a bus bypass segment, also called a queue jump, affects traffic on a signalized arterial. Residual queues form at the site’s critical bottleneck and expand to street links upstream. A bypass, when designed to serve a bus stop as per AASHTO guidelines, is shown to reduce bus delays—if the stop resides on a congested link that is upstream of the one feeding traffic to the critical bottleneck. In contrast, using a bypass for a bus stop located immediately upstream of the critical bottleneck starves that bottleneck of flow. The damage thus...

How and When Cordon Metering Can Reduce Travel Times

Doig, Jean
Daganzo, Carlos F.
Cassidy, Michael J.
2024
The paper addresses two questions regarding cordon metering that have until now gone unanswered. The first of these pertains to how and where a metered cordon ought to be placed in a city to be of greatest benefit. A simple 3-step rule is proposed that can be readily applied in real settings, and that we call the cordon layout conjecture, or CLC. Its use is shown to minimize the overall travel time...

An Analysis of HOT Lanes in North Carolina

Benjamin, JM
Sakano, R
McKinney, B
Khattak, AJ
Rodriguez, DA
Gaskin, C
2007

Many medium and small-size metropolitan areas in the U.S. face increasing traffic problems similar to large metropolitan areas. These metropolitan areas have responded primarily by expanding their road network and capacity. This paper explores the possibility of using a HOT lane in a medium-size metropolitan area for the same purpose. A detailed analysis and a suggested HOT lane solution are prepared for Greensboro-Winston-Salem-High Point metropolitan area. While high congestion are not widespread in the region now, a highway corridor is identified based on forecasted high...

Regional Intelligent Transportation Systems Architectures and the Competitive Region

Rodriguez, DA
Muñoz-Loustaunau, A
Pendleton, T
Sussman, JM
1998

The role of an architecture for deploying intelligent transportation systems in finding solutions to regional transportation problems is analyzed. The concept of a competitive region, a region with changing economic interests, stakeholders, and borders, is reviewed. The competitive region motivates finding solutions to transportation problems of regional scope. The concept of a regional system architecture is then introduced as a catalyst for reaching coordinated regional solutions. The regional architecture’s flexibility and ability to bring different stakeholders together make it...

Analysis of Bogota's Bus Rapid Transit System and its Impact on Land Development

Taiga, F
Rodriguez, DA
2004

Recent experiences in Latin American cities supporting world-class public transportation systems have resulted in the creation of livable spaces with a significant potential to spur land development. In cities like Bogota, Colombia, and Curitiba. Brazil, bus rapid transit (BRT) has re-emerged as a cost-effective transportation alternative for satisfying growing demands for urban mobility. Bogota's BRT system has allowed for a 32 percent reduction in average travel times and significant reduction in accident and air pollution levels along the busway corridors. Although previous...

Expedited Crash Investigation - With Use of Technologies for Documentation and Processing

Chan, Ching-Yao
Lian, Thang
Ko, Jeff
2007

The mobility and efficiency of California highways are impeded by the recurrent and non-recurrent congestion on a daily basis. Roadway incidents, especially collisions, often result in traffic congestion and travel delays. This project is initiated to explore the use of technologies that will potentially bring direct and immediate benefits to the law enforcement officers and other personnel who are involved in the handling of collision sites and subsequent investigations. The work carried out in this project includes three major components: (1) The experimentation of integrated vehicular...

Economic Impact of Traffic Incidents on North Carolina’s Interstate Facilities: Final Report, January 2008

Khattak, AJ
Teague, C
Pan, X
Fan, Y
Rodriguez, D
2008

Unexpected delays due to traffic incidents represent a significant proportion of overall delay, especially in urban areas. The resulting uncertainty can represent major costs to businesses and travelers, as well as restrict employment opportunities. This study focuses on North Carolina’s Interstate facilities and businesses across the State that rely on these facilities for their daily operations and are influenced by traffic congestion due to their shipping needs. The first portion...

Impacts of Commute Trip Reduction Programs, Rail Station Area Built Environment Changes, and Ride-Hailing Services on Traveler Behavior

Li
Rodriguez, D
Montilla, M
Chatman, D
Chen, P
Yang, X
Winters, P
2022

This project consists of three related studies investigating strategies to address urban congestion: a) employer-based travel demand management strategies, b) improvement of transit station area built environments, and c) understanding the impacts of ride-hailing. Collectively, the three studies represent complementary strategies to address urban congestion. However, each of them focuses on a particular approach from managing demand side incentives to supply side service disruptions.

Travel Times on Changeable Message Signs: Pilot Project

Chen, Chao
2004

We describe a system to display real time travel times on Changeable Message Signs (CMS) in California. CMS's show dynamic information and allow the Traffic Management Center (TMC) to communicate to drivers information about traffic diversion, incidents, and delays. This type of service is deployed in other parts of the country and world and has been shown to be useful. For this project, we implemented a system that uses existing algorithms for travel time estimation and prediction.