Intelligent Transportation Systems

Structure of Competitive Transit Networks

Daganzo, Carlos F.
2009

This paper describes the network shapes and operating characteristics that allow a transit system to deliver a level of service competitive with that of the automobile. To provide exhaustive results for service regions of different sizes and demographics, the paper idealizes these regions as squares, and their possible networks with a broad and realistic family that combines the grid and the hub-and-spoke concepts. The paper also shows how to use these results to generate master plans for transit systems of real cities.The analysis reveals which network structure and technology (Bus, BRT...

On the perceptibility of safety systems

Grembek, Offer
Daganzo, Carlos F.
2010

The perceptibility of a safety system is defined as the extent to which the system can be perceived by the senses or the mind. The objective here is to study which safety systems are more easily perceived by the user and to identify design attributes that affect this level of perception. A web-based, pairwise comparison survey was conducted to evaluate the perceptibility of fifteen safety systems ranging from traffic safety systems to consumer safety. The analytic hierarchy process was applied to estimate the perceptibility levels and rank the safety systems. The results show that...

Gap acceptance for vehicles turning left across on-coming traffic: Implications for Intersection Decision Support design

Ragland, David R.
Arroyo, Sofia
Shladover, Steven E.
Misener, James A.
Chan, Ching-Yao
2005

A left-turning vehicle (Subject Vehicle, SV) attempting to cross the path of an oncoming vehicle (Principal Other Vehicle, POV) at an intersection typically does not have the right of way. The main task of the SV driver is to find an adequate opportunity in opposing traffic to initiate the left-turn maneuver. To reduce the probability of a conflict, warning systems, such as Intersection Decision Support (IDS) systems, are being developed. These systems alert drivers of SV vehicles attempting to negotiate a left turnabout traffic approaching from the opposite direction. The current paper (i...

San Francisco PedSafe II Project Outcomes and Lessons Learned

Hua, Jenna
Gutierrez, Nicolas
Banerjee, Ipsita
Markowitz, Frank
Ragland, David R
2009

This paper presents the project outcomes and lessons learned from the San Francisco PedSafe, a comprehensive pedestrian safety planning and engineering project funded by the Federal Highway Administration. It assesses the effectiveness of the Phase I pedestrian safety plan targeted to higher-injury areas by evaluating the Phase II implementation of a range of mostly low-to-moderate-cost innovative safety improvements.A total of 13 countermeasures (comprised of nine general engineering countermeasures and four Intelligent Transportation Systems (ITS) countermeasures) were implemented by the...

Impact of Pedestrian Presence on Movement of Left-Turning Vehicles: Method, Preliminary Results & Possible Use in Intersection Decision Support

Banerjee, Ipsita
Shladover, Steven E
Misener, James A
Chan, Ching-Yao
Ragland, David R
2004

Warning systems are being developed for left-turning vehicles at intersections where protected left-turns are not warranted or cannot be provided, based on limitations of right of way or intersection capacity. These are meant to provide warnings to left-turning vehicles of vehicles approaching from the opposite direction, when the time to turn may be deemed unsafe. To implement these warning systems, it is necessary to estimate in near real time, the probability of conflict between the two approaching vehicles. A study is being conducted with the help of video and radar at various...

New GIS Mapping Features in TIMS Feb 22, 2013

Bigham, John
2013

This is a recording of a presentation made by SafeTREC GIS Project Manager John Bigham explaining new features to the Transportation Injury Mapping System website, tims.berkeley.edu

Evaluation of the Accuracy of Global Positioning System Coordinates for Collision Locations in California

Bingham, John
Strang, Garrett
Oum, Sang Hyouk
2014

Traffic collision reports typically provide descriptive locations indicating where a collision occurred and referencing the nearest intersection. Global Positioning System (GPS) technology can be used to provide latitude and longitude coordinates in addition to the descriptive location and many states now include GPS coordinates in collision reports. However, research has shown that there is potential for numerous errors when police agencies use GPS to complete traffic collision reports. In California, GPS coordinates have been included in the statewide collision database since 2006, but...

A Review of ITS-Based Pedestrian Injury Countermeasures

Bechtel, Allyson K
Geyer, Judy
Ragland, David R
2003

Crashes between motor vehicles and pedestrians caused at least 4,882 deaths and about 78,000 injuries in 2001 in the United States. In recognition of these troubling statistics, many public and private institutions look to Intelligent Transportation Systems (ITS) technologies. Few resources are available to provide a comprehensive summary of the effectiveness of these options. This report reviews previous scientific evaluation of red light enforcement cameras, illuminated walk signal push buttons, automated pedestrian detection systems for traffic signals, flashing crosswalk lights,...

A Database for Active Transportation Infrastructure and Volume

Proulx, Frank R.
Zhang, Yuanyuan, PhD
Grembek, Offer, PhD
2014

Information about pedestrian infrastructure and volume is indispensable to monitoring, evaluating, and improving the environment for comfortable and safe walking. However, determining and organizing the various types of data in a way that is easy to update and analyze can present challenges. This study designed and developed a relational database for pedestrian infrastructure and volume, and comprises two core components (node table and approach table) and several sub-components (tables for crosswalks, sidewalks, buffers, signs, transits, bikeways, bicycle parking, and volumes). Important...

An Intensive Pedestrian Safety Engineering Study Using Computerized Crash Analysis

Ragland, David R
Markowitz, Frank
MacLeod, Kara E
2003

Over the past year, the San Francisco Department of Parking and Traffic (DPT) conducted an intensive pedestrian-safety engineering study, the PedSafe Study. PedSafe was funded by the Federal Highway Administration (FHWA)*, which also funded companion studies in Las Vegas and Miami. The study was designed to analyze pedestrian injuries by zones (i.e., neighborhoods or districts) and to identify those most amenable to prevention efforts. The DPT expects to utilize the methodology and information from the PedSafe study to help shape a citywide pedestrian master plan. This paper describes the...