Roads/Highways

Deploying Underutilized Bus Lanes at Key Nodes in a Road Network

Guler, Ilgin
Cassidy, Michael
2010

The authors of this working paper explain that the operation of buses in mixed traffic flow can be impeded by congestion, leading to unreliable and slow service. Similarly, buses that stop frequently for passengers interfere with the flow of general traffic. Dedicated lanes provide a means for buses to bypass car queues, but in cases where bus flow is low, converting a general purpose lane to a bus-only lane will delay car traffic. The authors describe innovative schemes for deploying bus lanes to serve low bus demand intermittently. Strategies to deploy underutilized bus lanes will be...

A congestion mechanism for uphill expressways, Part I: the shoulder lane "release valve"

Patire, Anthony D.
Cassidy, Michael J.
2010

A mechanism is unveiled by which congestion forms and persists near the base of an uphill expressway segment, causing significant reductions in output flow. The traffic condition in the expressway's shoulder lane is key to the mechanism. When shoulder-lane flow was low, drivers maneuvered around speed disturbances that periodically arose in the median lane. The shoulder lane accommodated high rates of vehicle migrations, thus acting as a "release valve" for the excess accumulation created by the speed disturbances. The release valve failed only when demand increased later in the rush. The...

China's Urban Transportation System: Issues and Policies Facing Cities

Cherry, Chris
2005

China is the most populous country in the world. With a population of 1.3 billion, meeting the housing and transportation needs of this vast country are on the forefront of the political and academic agenda in China and throughout the world. China has experienced phenomenal economic and social growth and as a result the Chinese have desired more mobility and living space. The effects of these desires are beginning to be seen in new auto oriented ex-urban developments that have larger living spaces than the traditional urban centers and whose road infrastructure is developed to support high...

Dual Influences on Vehicle Speeds in Special-Use Lanes and Policy Implications

Jang, Kitae
Cassidy, Michael J.
2011

Slow speeds in a special-use lane, such as a carpool (HOV) or bus lane, can be due to both high demand for that lane and slow speeds in the adjacent regular-use lane. These dual influences are confirmed from months of data collected from all freeway carpool facilities in the San Francisco Bay Area. Both influences hold for other types of special-use lanes, including bus lanes. New US regulation stipulating that most classes of low-emitting vehicles, or LEVs, be banned from slow-moving carpool lanes. While LEVs invariably constitute only about 1 percent of the freeway traffic demand in the...

Performance Measures for Complete, Green Streets: A Proposal for Urban Arterials in California

Sanders, Rebecca
Macdonald, Elizabeth
Anderson, Alia
2010

The California Department of Transportation (Caltrans or “Department”) manages more than 15,000 miles of state highways, ranging in scale and function from local streets to interstate highways. Historically, Caltrans has been governed by the principles of highway engineering, which focus on providing mobility to motorized vehicles. Over the past decade, however, the Department has joined in a national movement to better incorporate non-motorized transportation and community-level outcomes into its transportation decision-making framework, embodied by the approach known as "Complete Streets...

Safe Routes to School Safety and Mobility Analysis

Orenstein, Marla R.
Gutierrez, Nicolas
Rice, Thomas M.
Cooper, Jill F.
Ragland, David R.
2007

This report evaluates the SR2S program for a number of mandated issues: (i) The effectiveness of the program in reducing crashes, injuries and fatalities involving children in the vicinity of the projects; (ii) The impact of the program on levels of walking and bicycling to school; and (iii) The safety benefits of the program in comparison with other highway safety programs.

Driver and Pedestrian Behavior at Uncontrolled Crosswalks in the Tahoe Basin Recreation Area

Mitman, Meghan Fehlig
Cooper, Douglas
DuBose, Brooke
2010

For more than thirty years, pedestrian safety studies have considered pedestrian-vehicle collision patterns and pedestrian and driver behavior at marked and unmarked crosswalks at uncontrolled crossings. Recent research in this area conducted by the UC Berkeley Traffic Safety Center [aka SafeTREC] on behalf of Caltrans, and summarized in a 2008 Transportation Research Record paper by Mitman et al., “The Marked Crosswalk Dilemma: Uncovering Some Missing Links in a 35-Year Debate,” was designed to fill key gaps in the literature by analyzing driver/pedestrian behavior and knowledge of right-...

A Dynamic Congestion Pricing Strategy for High-Occupancy Toll Lanes

Jang, Kitae
Chung, Koohong
2010

High Occupancy Toll (HOT) lanes are emerging as a solution to address the underutilization of High Occupancy Vehicle (HOV) lanes and also means of generating revenue for state department of transportation. This paper proposes a method for dynamically determining the HOT toll price in response to the changes in traffic condition and documents procedures for estimating parameters needed for the proposed pricing strategies: revenue maximization and delay minimization. The proposed strategies have been applied to 14-miles of freeway segment in the San Francisco Bay Area, and the findings show...

Providing Intersection Decision Support under Challenging Conditions

Shladover, Steven E.
VanderWerf, Joel
Ragland, David R.
2005

This paper describes the results of simulation studies to determine how effectively left-turning drivers can be alerted to imminent conflicts with opposing traffic under difficult operating conditions and with limited detector capabilities. These conditions include approaching vehicles changing speed in locations that are not covered by detectors and detectors that may only be able to detect vehicle presence, but not speed. In cases without direct speed detection, one may try to rely on historical speed statistics to estimate the speed of approaching traffic, but unless the approach speeds...

Complete Streets: From Policy to Practice in the San Francisco Bay Area

Pande, Swati, M.S.,MPP
Martinez, Martin MPP
2014

This paper describes how regional funding guidelines can affect local adoption of Complete Streets projects. The Metropolitan Transportation Commission (MTC), the regional Metropolitan Planning Organization for the nine-county Bay Area region in California, has developed a funding approach called the One Bay Area Grant (OBAG) for the allocation of funds for the 2012-2016 Congestion Mitigation and Air Quality (CMAQ) and Surface Transportation Program (STP) across the Bay Area. Each jurisdiction receiving funding through OBAG was required to demonstrate compliance with Complete Streets (CS)...