ITS Berkeley

System Optimum Diversion of Congested Freeway Traffic

Laval, Jorge A.
Munoz, Juan Carlos
2002

We study the system optimum dynamic traffic assignment (SODTA) in a network consisting of a freeway and neighboring city streets. There is only one bottleneck in the freeway and every destination is somewhere downstream of the bottleneck. Vehicles can be diverted through off-ramps leading to alternative local street routes. We formulate the problem and determine a graphical solution procedure based on Newell's cumulative plots, which yields the optimal diverted flow over time. On-ramps can be conveniently incorporated in this procedure yielding SO metering rates. The following variants are...

Airports and the General Conformity Process

Amin, Ratna S.
2001

Air quality conformity refers to the process wherein federally supported plans, programs and projects are shown to meet the air quality requirements of the Clean Air Act Amendments (CAAA) and the applicable State Implementation Plan (SIP). Transportation conformity refers to actions approved or funded by the Federal Highway Administration or the Federal Transit Administration. General conformity refers to projects approved or funded by other federal agencies. Airport projects are usually subject to general conformity rules. The general conformity process has provoked several contradictory...

Impacts of California's Graduated Licensing Law of 1998: An assessment by the Institute of Transportation Studies at UC Berkeley of the effects of the law on fatal and injury crashes of 16 year-old drivers

Cooper, Douglas
Gillen, David
Atkins, Frank
2004

In July 1998 California changed its graduated driver licensing laws (GDL) for new drivers under the age of 18 to include restrictions on hours of driving, carrying teen-age passengers, and requiring more adult supervised driving practice. With fatal and injury crash data from California's Statewide Integrated Traffic Records System, this study, sponsored by the California State Automobile Association, used standard regression analysis as well as the Bai-Perron stochastic multiple structural break model to determine the effect of the law on teen-age passengers and crash rates of 16 year-old...

To Pool or Not to Pool? Understanding the Time and Price Tradeoffs of OnDemand Ride Users – Opportunities, Challenges, and Social Equity Considerations for Policies to Promote Shared-Ride Services

Shaheen, Susan, PhD
Lazarus, Jessica
Caicedo, Juan
Bayen, Alexandre, PhD
2021

On-demand mobility services including transportation network companies (also known as ridesourcing and ridehailing) like Lyft and Uber are changing the way that people travel by providing dynamic mobility that can supplement public transit and personal-vehicle use. However, TNC services have been found to contribute to increasing vehicle mileage, traffic congestion, and greenhouse gas emissions. Pooling rides ⎯ sharing a vehicle by multiple passengers to complete journeys of similar origin and destination ⎯ can increase the average vehicle occupancy of TNC trips and thus mitigate some of...

A Behavioral Theory of Multi-Lane Traffic Flow Part I: Long Homogeneous Freeway Sections

Daganzo, Carlos F.
1999

This paper proposes a macroscopic behavioral theory of traffic dynamics for homogeneous, multi-lane freeways. The theory makes predictions for separate groups of lanes while recognizing that the traffic stream is usually composed of aggressive and timid drivers. Its principles are so simple that non-scientist drivers can understand them. The simplest version of the theory, which is described in its full complexity without calculus, is shown to be qualitatively consistent with experimental observations, including the most puzzling. Its predictions agree with the following phenomena: (i) the...

High Accuracy Location Based Services CostBenefit Study: Final Report

Goodliss, Adam
Manasseh, Christian
Ekambaram, Venkatesan
Sengupta, Raja
Kanafani, Adib
Ramchandran, Kannan
2011

This report presents a benefit and cost study of a Cooperative High‐Accuracy LOcation (C‐HALO) service. A High Accuracy Location service should be ubiquitous and reliable as the GPS constellation. A survey of the literature on location services reveals a body of work on the benefits of a high accuracy location service. Focusing on road travel, benefits are estimated to be between $160-$320 billion dollars over slightly more than 20 years. The benefits arise from smoother traffic flow on the roads leading to reduced travel delays, and fewer accidents leading to reduced injuries and saved...

The Full Cost Of Intercity Transportation - A Comparison Of High Speed Rail, Air And Highway Transportation In California

Levinson, David
Gillen, David
Kanafani, Adib
Mathieu, Jean-michel
1996

The Full Cost of Intercity Transportation Page ES-1 This study evaluates the full cost of three modes of intercity transportation: air, highway, and high speed rail. The evaluation is done within the context of the California Corridor, connecting the Los Angeles Basin and the San Francisco Bay Area. The purpose of evaluating full cost is to compare the economic implications of investment in, or expansion of, any of these three modes. The scope of the analysis is full transportation cost. Full transportation costs includes external, or social cost, in addition to the internal costs of...

The Impact of COVID-19 on the Mobility Needs of an Aging Population in Contra Costa County

Ragland, David R, PhD, MPH
Schor, Glenn, PhD, MPH
Felschundneff, Grace
2020

In 2018, SafeTREC conducted a survey on transportation mobility issues among older adults in California. A follow-up survey planned for 2020, just as the COVID-19 pandemic changed life for all residents, was redesigned to assess mobility needs and changes during the Shelter-in-Place order and focused on COVID-19 impacts. Results indicate that the COVID-19 pandemic and subsequent Shelter-in-Place order have had a major impact on senior mobility. Communications for many were restricted to phone, email, texts, social media and video chats. Among those with a medical problem, just over 60%...

Empirical Study of Ramp Metering and Capacity

Cassidy, Michael J.
Rudjanakanoknad, Jittichai
2002

Traffic data near the junction of a single-lane on-ramp (with a ramp meter) and a three-lane freeway were measured for six weekdays during the rush and studied. On each of these days, the merge became a bottleneck with queue discharge rates that were substantially lower than the flows that had passed the merge prior to the bottleneck's activation. On some days, these earlier high flows persisted for many minutes. The bottleneck always occurred when inflows from the on-ramp surged in the presence of high flows arriving from the freeway. Often, the on-ramp surges persisted for no longer than...

Measuring the influence of recurring sporting events on freeway characteristics

Seeherman, Joshua
Anderson, Paul
2017

Freeway traffic is subject to the effects of recurring and non-recurring events. Changes in the traffic stream as a result of recurring special events, specifically sports, is an area that is not well researched. This study examined freeway detectors adjacent to two baseball stadiums in California to analyze the contribution of a baseball game to freeway flow and occupancy for weekday evening games. In addition, hourly volumes on local rail transit were analyzed in the San Francisco case. Findings include a statistically significant effect of baseball increasing the flow by approximately 1...