S.J. Abolosu-Amison and A.W. Sadek, University of Vermont

Ongoing

Measuring changes in arterial traffic flow during adverse weather and developing microsimulation adjustment factors. Second stage will use model to develop weather-dependent arterial timing plans

Jean C. Andrey and Daniel Unrau, University of Waterloo

2006

Modeled the impact of light rain on urban expressway conditions. Looked at several traffic variables under dry and wet conditions and addressed the safety implications of driver adjustment to rain during night and day conditions.

Conrad Dudek, Brooke Ulman, Nada Trout, Melisa Finley and Gerald Ullman, Texas Transportation Institute

2006

Focus groups and human factors studies were used to help improve the effectiveness of DMS messages under different situations, including inclement weather. The methodology can provide a useful model, or could be built upon, to help identify driver response to inclement weather.

Reuben Goldblatt and Kevin Weinisch, KLD Associates

2005

The case study dealt with a simulated evacuation of an area impacted by a nuclear power plant emergency. This case study addressed pretrip behavior and some of the methods may be adaptable to pretrip decisions related to adverse weather.

S. Peeta and W. Zhou, Purdue University and Indiana DOT

2004

This study developed a simulation model that focused on the behavior of nontruck drivers when encountering trucks. Behavior during adverse weather was one of the factors evaluated. Experiments used data from the Borman Expressway data and from stated-preference surveys of nontruck drivers.

Henry C. Lieu and Shiow-Min Lin, Turner-Fairbank Highway Research Center, FHWA

2004

The purpose of this study was to use CORSIM to illustrate a procedure for assessing the benefits of retiming traffic signals in adverse weather.

Richard Dowling and Michael Carroll (Dowling Associates), Alexander Skabardonis (UC Berkeley Institute of Transportation Studies, Wang Zhongren (Caltrans)

2004

A methodology is presented for estimating and predicting the total annual traffic congestion attributable to recurrent and nonrecurrent congestion. Weather delays are estimated based on frequency of occurrence and capacity reductions during adverse weather.

Panos D. Prevedouros, Ph.D., University of Hawaii at Manoa

2003

This study included a review and synthesis of research conducted on the impact of wet conditions on speed and capacity over approximately 30 years. The report compared HCM factors for adverse weather to those found in the synthesized studies.

A. Varhelyi

2002

This research looked at potential design and use of an in-car system that would adaptive speed controls to guide driver behavior under adverse weather conditions. The report focused on system design considerations and further research required.

K. Sasaki, T. Tamuro and K. Saito

2002

The objective of the paper was to evaluate users’ willingness to pay for traffic safety information, primarily regarding fixed point road safety information such as safe curve speed. The methodology could be applied to pretrip information related to weather.

K. M. Kockelman

1998

This study modeled flow-density relationships over roadway segments in adverse weather. Some disaggregation of various markets was tested.

Asad Khattak (PATH Program, UC Berkeley), Moshe Ben-Akiva and Amalia Polydoropoulou (MIT Center for Transportation Studies)

1996

This study used stated-preference and behavioral surveys to test traveler response to pretrip information on congestion. The results showed prescriptive pretrip information does increase the likelihood that travelers will modify their route or time of departure.

A.T. Ibrahim and F. L. Hall

1994

This study used Freeway TMS data and weather data from Ontario’s Queen Elizabeth Way to look at the effect of adverse weather on flow-occupancy and speed-flow relationships. Results indicated that the speed-flow function shifted downward during adverse conditions and that maximum observed flow rates were also reduced.

F.L. Hall and D. Barrow

1988

This study looked at the relationship between flow rates and roadway occupancies on freeways. This study also noted that the slope of the line relating flow to occupancy decreases as weather conditions deteriorate. The paper also noted the importance of developing flow-occupancy relationships on

S.J. Abolosu-Amison, A.W. Sadek, and W. Elessouki, University of Vermont

2004

This study involved collection of data over a three month period via videotape from a signalized intersection in Burlington, VT. The study looked at the feasibility of developing special timing plans for adverse weather conditions. The study showed that saturation headways are impacted by adverse weather but start-up times are not. The implementation of special plans did appear to be beneficial.

Pirkko Rama, Technical Research Centre of Finland

2001

The study looked at the effects of using VMS to provide motorists with updated and local weather and road condition information. Different sign configurations and technologies were studied. Signs were used to lower speed limits and suggest greater headways. Motorists responded positively to these efforts.

M. Kyte, Z. Khatib, P. Shannon, E. Kitchener

2001

The impact of poor weather conditions on free-flow speed on a rural Interstate was evaluated. It was found that pavement condition, visibility and wind all had an impact on free flow speed.

Keith Knapp, Dennis Kroeger and Karen Glese, Iowa State University Center for Transportation Research and Education

2000

The primary focus of this extensive study was to estimate the impacts of winter storm events on traffic volume, speed and crash rates on a rural Interstate highway. An initial study was conducted using secondary, archived data. This was followed by a second phase that involved field collection of weather and traffic data using both manual methods and video detection equipment. Significant speed reductions were estimated and the results were similar during both phases of the study.

J. Perrin, University of Utah

2000

This paper presents results of the ADVISE system, which uses DMS to recommend speeds to drivers during periods of low visibility. It was found that the system reduced variability since faster drivers slowed down and overly cautious drivers reacted to a recommendation that they could go faster.

Pamela J Maki, SEH Consultants

1999

This study used both secondary and primary data to look at the feasibility of implementing traffic signal timing plans to address adverse weather conditions in the Twin Cities of Minnesota. Weather and traffic data were both collected at the site and a Synchro analysis was conducted to determine whether alternative timing plans could reduce delay under adverse conditions.

DJ Holdener

1998

Wet and dry speed data were collected along I-290 in Houston and analyzed using ANOVA. Speeds were measured at different times of day and significant differences were found between wet and dry conditions.

JH Hogema, Delft Hydraulics Laboratory

1996

This study investigated the effects of rain on traffic volume and behavior in Holland. Rain did not impact volumes but did result in reduced speeds and longer headways.