Piyali Chaudhuri - Academia.edu (original) (raw)

Uploads

Papers by Piyali Chaudhuri

Loop detectors report traffic characteristics in real time. They are at the core of traffic contr... more Loop detectors report traffic characteristics in real time. They are at the core of traffic control process. Intuitively, one would expect that as density of detection increases, so would the quality of estimates derived from detector data. However, as detector deployment increases, the associated operating and maintenance cost increases. Thus, traffic agencies often need to decide where to add new detectors and which detectors should continue receiving maintenance, given their resource constraints. This paper evaluates the effect of detector spacing on freeway travel time estimation. A freeway section (Interstate-15) in Salt Lake City metropolitan region is examined. The research reveals that travel time accuracy does not necessarily deteriorate with increased detector spacing. Rather, the actual location of detectors has far greater influence on the quality of travel time estimates. The study presents an innovative computational approach that delivers optimal detector locations th...

This paper analyzes a wide range of incidents and responses for the set of critical locations on ... more This paper analyzes a wide range of incidents and responses for the set of critical locations on a test Salt Lake Valley freeway network. It uses VISSIM microsimulation to determine optimal responses under various incident conditions. As expected, the resulting degree of incident disruption is mitigated by the speed of response and the proportion of drivers who divert. However, for certain minor incidents, a “laid back” approach is the better option. This counter intuitive finding can be characterized as “too much diversion, too soon, for too many drivers”. This indicates the importance of efficient use of resources when responding to traffic incidents.

World Review of Intermodal Transportation Research, 2011

Freeway performance measures are extracted from Traffic Monitoring Stations (TMS) which gather tr... more Freeway performance measures are extracted from Traffic Monitoring Stations (TMS) which gather traffic volume and speed data. Reported freeway speeds are usually aggregated over periods of 20 or 30-second or 1, 5, or 15-minute by traffic agencies. This paper examines the accuracy and reliability of reported TMS detector speeds. The study compares speeds collected by GPS-equipped probe vehicles with aggregated detector speeds. The paper evaluates how various aggregation intervals impact accuracy and reliability of TMS detector speeds and determines the optimal aggregation interval. Results indicate that shorter aggregation intervals are appropriate for high variability traffic conditions during peak periods.

The contents of this report reflect the views of the authors, who are responsible for the facts a... more The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

The contents of this report reflect the views of the authors, who are responsible for the facts a... more The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Center program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

Traffic Operations Centers (TOC) deal with incidents. These incidents vary by location, time of d... more Traffic Operations Centers (TOC) deal with incidents. These incidents vary by location, time of day, and degree of disruption. Operator responses vary by how quickly they are implemented and the degree of operational actions they take. Operators can react instantaneously, or they can wait to assess the incident’s impact. They can divert traffic from an entire highway or simply implement a mild variable message. The paper presents an analysis of critical incident locations on a test Salt Lake Valley freeway network. The microsimulation modeling is through VISSIM. We define Closure Level as the percentage of lanes closed due the incident. The Incident Duration is the interval from lane closure to traffic taking back the obstructed lane or lanes. The Response Time is the interval between the onset of the modeled traffic impact and the implementation of the Variable Message Sign Levels (VMS Levels). The VMS Levels are four levels of driver response to the intensity of the message. While no messages are offered, we identify a range of proportion of drivers who comply with diversion recommendations. This paper analyses a wide range of incidents and responses. As expected, the resulting degree of incident disruption is mitigated by the speed of response and the proportion of drivers who divert. However, for certain minor incidents, a “laid back” approach is the better option. This counter intuitive finding can be characterized as “too much diversion, too soon, for too many drivers”.

World Review of Intermodal Transportation Research, 2011

The contents of this report reflect the views of the authors, who are responsible for the facts a... more The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Center program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.