Professor to Publish Two Papers

A paper written by Dr. Clara Fang, assistant professor of Civil, Environmental, and Biomedical Engineering, with Joseph Rimiller and Najib Habesch of Urban Engineers, Inc., in Hartford, Connecticut, titled “A Simplified Empirical Bayesian Method to Safety Evaluation of Traffic Calming Treatment for Urban Road Systems” is featured today on
EurekAlert! an online, global news service operated by AAAS, the science society. (EurekAlert! provides a central place through which universities, medical centers, journals, government agencies, corporations and other organizations engaged in research can bring their news to the media. EurekAlert! also offers its news and resources to the public. EurekAlert! features news and resources focused on all areas of science, medicine and technology. Click here to see the release.) The release is expected to be picked up by newswires and journalists worldwide.

The paper will appear in the International Journal of Intelligent Systems Technologies and Applications (2009, 6, 349-363). The paper reports on an analysis of before and after crash data for various traffic calming devices to determine which were most effective in reducing accidents.

Hartford was the first U.S. city to develop and implement a traffic calming master plan that included mini-roundabouts, curt extensions, speed tables, parking chicanes, bicycle lanes, and the elimination of excess lanes from specific streets. To determine the actual effects of these devices, Fang, Rimiller and Habesch used an empirical Bayesian method to analyze the before and after statistics and compared crash rates with and without such devices for the same time period.

They report that all the safety devices led to fewer crashes, though the higher the before rate of crashes, the lower the after rate, so that streets with few crashes before the implementation of the devices had few crashes afterward. However, streets with reduction in lanes saw a significant reduction in crash rates, due primarily to a reduction in speed on those streets.

Dr. Fang also has written “Fuzzy Data Mining Approach for Quantifying Signalized Intersection Level of Services Based on User Perceptions,” which will appear in the Journal of Transportatoin Engineering, Vol. 135, no. 6, June 2009, published by the American Society of Civil Engineers. Her co-author on this paper is Dr. Kelley Pecheux of the Science Application International Corporation.

The paper reports on work performed by Fang and Pecheux to create a user perception database from the reactions of 100 subjects assessing 24 approaches to intersections in terms of stopped delay and rating of service. The researchers considered how users perceive quality of service at signalized intersections and how many levels of service (LOS) drivers can perceive. Their conclusion is that drivers are able to differentiate among six levels of service—but not the ones in the existing Highway Capacity Manual. They propose six new levels of service in the fuzzy domain.

CETA congratulates Dr. Fang and all of her co-authors on the publication of their work.