Environment

Relationships Among Urban Freeway Accidents, Traffic Flow, Weather and Lighting Conditions

Golob, Thomas F.
Recker, Wilfred W.
2001

Linear and nonlinear multivariate statistical analyses are applied to determine how the types of accidents that occur on heavily used freeways in Southern California are related to both the flow of traffic and weather and ambient lighting conditions. Traffic flow is measured in terms of time series of 30-second observations from inductive loop detectors in the vicinity of the accident prior to the time of its occurrence. Results indicate that the type of collision is strongly related to median traffic speed and to temporal variations in speed in the left and interior lanes. Hit-object...

Design Of An Extended Architecture For Degraded Modes Of Operation Of AHS

Lygeros, John
Godbole, Datta N.
Broucke, Mireille E.
1995

In this paper, the authors propose a hierarchical control architecture for dealing with faults an adverse environmental conditions on an Automated Highway System (AHS). The design builds on a previously designed control architecture that works under normal conditions of operation. The faults that are considered in the design are classified according to capabilities remaining on the vehicle or roadside after the fault has occurred. Information about these capabilities is used by the supervisors in each of the layers to select appropriate control strategies. The extended control strategies...

PEDAMACS: Power Efficient and Delay Aware Medium Access Protocol for Sensor Networks

Coleri, Sinem
Varaiya, Pravin
2004

We consider a class of sensor networks with two special characteristics. First, the nodes periodically generate data for transfer to a distinguished node called the access point. Second, the nodes are (transmit) power and energy limited, but the access point, which communicates with the ‘outside world’, is not so limited. Such networks might be used for instance when a geographically distributed physical process, such as traffic on a freeway or at an urban street intersection, is periodically sensed for purposes of process control. We propose a medium access control scheme, called PEDAMACS...

Collecting Road Traffic Data Using ALOHA Mobile Radio Channel

Linnartz, Jean-Paul M.G.
Gamba, David P.
1993

This report proposes a spectrum efficientsolution for transmitting link travel times from vehicles to a central infrastructure. The performance of an ALOHA mobile radio system for this application is studied analytically. The average number of new updates per minute and the expected time lapsed since the latest update of the road traffic situation in a particular street section is obtained. Results show that in an urban environment, a single (cellular) radio channel has sufficient capacity if receivers are located every 5 to 10 km.

Investigation Of An Optical Method To Determine The Presence Of Ice On Road Surfaces

Misener, James
1998

This report presents a review of alternative techniques to determine the presence of ice on road surfaces. It examines techniques ranging from passive, in-pavement technologies, to different remote sensing techniques. The author presents the Polarized Reflectance Infrared Signature Method (PRISM) technique which uses differences in measured near infrared reflectance between ice, water and dry road due to absorption, in addition to the effect of polarization to discount the contribution of specutacular reflectance off the front surface.

Travel Effects of a Suburban Commuter Carsharing Service: CarLink Case Study

Shaheen, Susan A.
Rodier, Caroline J.
2005

Since 1998, carsharing programs (or short-term auto rentals) in the U.S. have experienced exponential membership growth. As of July 2003, 15 carsharing organizations collectively claimed 25,727 members and 784 vehicles. Given this growing demand, decision makers and transit operators are increasingly interested in understanding the potential for carsharing services to increase transit use, reduce auto ownership, and lower vehicle miles traveled. However, to date, there is only limited evidence of potential program effects in the U.S. and Europe. This paper presents the travel effects of...

Achieving Zero-Emission Mobility: The Role of Innovative Electric Vehicle Companies

Argote, Juan
Lee, Albert
Hernandez, Maribel
2016

On April 28, 2016, UCCONNECT hosted a symposium in Berkeley, CA on Achieving Zero-Emission Mobility: The Role of Innovative Electric Vehicle Companies. The symposium provided a platform for innovative and trendsetting electric vehicle (EV) companies to explain their latest business models and show how they can add value and contribute to the national dialogue on the transformation needed to achieve zero-emission transportation. Focus was also placed on identifying strategies that could potentially broaden the clean-transportation conversion by increasing “zero-emission vehicle” (ZEV)...

Future of Mobility White Paper

Shaheen, Susan, PhD
Totte, Hannah
Stocker, Adam
2018

Transportation is arguably experiencing its most transformative revolution since the introduction of the automobile. Concerns over climate change and equity are converging with dramatic technological advances. Although these changes – including shared mobility and automation – are rapidly altering the mobility landscape, predictions about the future of transportation are complex, nuanced, and widely debated. California is required by law to renew the California Transportation Plan (CTP), updating its models and policy considerations to reflect industry changes every five years. This...

SB 743 Implementation: Challenges and Opportunities

Barbour, Elisa
Chatman, Daniel G.
Doggett, Sarah
Yip, Stella
Santana, Manuel
2019

California’s Senate Bill (SB) 743, enacted in 2013, marks a historic shift in how the traffic impacts of development projects are to be evaluated and mitigated statewide. To help achieve state climate policy and sustainability goals, SB 743 eliminates traffic delay as an environmental impact under the California Environmental Quality Act. State implementing guidelines for SB 743 instead require an assessment of vehicle miles traveled (VMT). The adoption of the guidelines sparked debate and raised far-reaching questions about development planning. Our research consisted of four parts. First...

Moving Towards A More Sustainable California: Exploring Livability, Accessibility, and Prosperity

Shaheen, Susan
Finson, Rachel
Bhattacharyya, Abhinav
Jaffee, Mark
2016

The Transportation Sustainability Research Center at UC Berkeley conducted a series of tasks to assist the California Department of Transportation (Caltrans) with an understanding of prosperity, accessibility, and livability metrics. Research findings were collected through a combination of literature reviews and expert interviews. Researchers found that prosperity, accessibility, and livability metrics all involve a component of cooperation with partner jurisdictions. A flexible approach that accounts for local and corridor considerations and evolves over time is emphasized. The white...