Empirical Studies on Traffic Flow in Inclement Weather

Weather causes a variety of impacts on the transportation system. While severe winter storms, hurricanes, or flooding can result in major stoppages or evacuations of transportation systems and they cost millions of dollars, day-to-day weather events such as rain, fog, snow, and freezing rain can have a serious impact on the mobility and safety of the transportation system users. These weather events can result in increased fuel consumption, delay, number of accidents, and significantly impact the performance of the transportation system. The overall goal of the research work undertaken in this study was to develop a better understanding of the impacts of weather on traffic flow. The research was intended to accomplish the following specific objectives: (1) study the impact of precipitation on macroscopic traffic flow parameters over a full range of traffic states; (2) study the impact of precipitation on macroscopic traffic flow parameters using consistent, continuous weather variables; (3) study the impact of precipitation on macroscopic traffic flow parameters on a wide range of facilities; (4) study regional differences in reaction to precipitation; and (5) study macroscopic impacts of reduced visibility. The work documented in this report was conducted in two parts: (1) literature review and development of a data collection and analysis plan, and (2) analysis and interpretation of the results. The recommended plan combined the use of macroscopic traffic data archives with archived weather data in order to meet the research goals that include achieving better understanding of the impacts of weather on macroscopic traffic flow. The results of the research conducted for this study were helpful identifying weather impacts of traffic flow in the three cities studied, Minneapolis-St. Paul, Baltimore and Seattle. No impacts were found on traffic stream jam density, but both rain and snow did impact traffic free-flow speed, speed-at-capacity and the capacity and speed parameters varied with precipitation intensity. The results of these analyses are documented in the report. This report concludes with some recommendations of future research related to weather and traffic flow. Several ideas are presented including enhancing the macroscopic analysis used in this study. Additional work is proposed related to human factors and microscopic traffic modeling.

[1]  B D Greenshields,et al.  A study of traffic capacity , 1935 .

[2]  L. A. Pipes.  An Operational Analysis of Traffic Dynamics , 1953 .

[3]  M. Lighthill,et al.  On kinematic waves I. Flood movement in long rivers , 1955, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[4]  M J Lighthill,et al.  ON KINEMATIC WAVES.. , 1955 .

[5]  P. I. Richards.  Shock Waves on the Highway , 1956 .

[6]  H. Greenberg.  An Analysis of Traffic Flow , 1959 .

[7]  G. F. Newell.  Nonlinear Effects in the Dynamics of Car Following , 1961 .

[8]  Louis A. Pipes,et al.  Car following models and the fundamental diagram of road traffic , 1967 .

[9]  E. R. Jones,et al.  THE ENVIRONMENTAL INFLUENCE OF RAIN ON FREEWAY CAPACITY , 1970 .

[10]  R. Lyman Ott.,et al.  An introduction to statistical methods and data analysis , 1977 .

[11]  黒田 孝次,et al.  Highway Capacity Manual改訂の動向--テイラ-教授の講演より , 1984 .

[12]  Adolf D. May,et al.  Traffic Flow Fundamentals , 1989 .

[13]  Ruediger Lamm,et al.  COMPARISON OF OPERATING SPEEDS ON DRY AND WET PAVEMENTS OF TWO-LANE RURAL HIGHWAYS , 1990 .

[14]  Rashad M Hanbali,et al.  TRAFFIC VOLUME REDUCTIONS DUE TO WINTER STORM CONDITIONS , 1993 .

[15]  Amal Ibrahim,et al.  EFFECT OF ADVERSE WEATHER CONDITIONS ON SPEED-FLOW-OCCUPANCY RELATIONSHIPS , 1994 .

[16]  R. Snowden,et al.  Speed perception fogs up as visibility drops , 1998, Nature.

[17]  P. J. Maki.  ADVERSE WEATHER TRAFFIC SIGNAL TIMING , 1999 .

[18]  A. Khattak,et al.  Mobility and Safety Impacts of Winter Storm Events in a Freeway Environment , 2000 .

[19]  David J. Groggel,et al.  Practical Nonparametric Statistics , 2000, Technometrics.

[20]  L. Chambers.  Linear and Nonlinear Waves , 2000, The Mathematical Gazette.

[21]  Joseph Perrin.  EFFECTS OF VARIABLE SPEED LIMIT SIGNS ON DRIVER BEHAVIOR DURING INCLEMENT WEATHER , 2000 .

[22]  Virginia P Sisiopiku.  VARIABLE SPEED CONTROL : TECHNOLOGIES AND PRACTICE , 2001 .

[23]  SOCIOECONOMIC IMPACTS OF HEAVY PRECIPITATION IN THE UNITED STATES , 2001 .

[24]  Michael Kyte,et al.  Effect of Weather on Free-Flow Speed , 2001 .

[25]  Shawn Turner,et al.  GUIDELINES FOR DEVELOPING ITS DATA ARCHIVING SYSTEMS , 2001 .

[26]  Peter T. Martin,et al.  Modifying Signal Timing During Inclement Weather , 2001 .

[27]  Pirkko Rämä,et al.  Effects of weather-controlled variable message signing on driver behaviour , 2001 .

[29]  Karl E Wunderlich,et al.  An Analysis of the Worst Commuting , 2002 .

[30]  Hesham Rakha,et al.  Comparison of Greenshields, Pipes, and Van Aerde Car-Following and Traffic Stream Models , 2002 .

[31]  Li Zhang,et al.  Identifying and Assessing Key Weather-Related Parameters and Their Impacts on Traffic Operations Using Simulation , 2003 .

[32]  V. Shah,et al.  ANALYSIS OF WEATHER IMPACTS ON TRAFFIC FLOW IN METROPOLITAN WASHINGTON, DC , 2003 .

[33]  Brian L. Smith,et al.  An Investigation into the Impact of Rainfall on Freeway Traffic Flow , 2003 .

[34]  Jean Andrey,et al.  A Temporal Analysis of Weather-related Collision Risk for Ottawa, Canada: 1990-1998 , 2003 .

[35]  Emily D. Sterzin.  Modeling influencing factors in a microscopic traffic simulator , 2004 .

[36]  Timothy J Lomax,et al.  LESSONS LEARNED: MONITORING HIGHWAY CONGESTION AND RELIABILITY USING ARCHIVED TRAFFIC DETECTOR DATA , 2004 .

[37]  Panos D. Prevedouros,et al.  Potential Effects of Wet Conditions on Signalized Intersection LOS , 2005 .

[38]  Hesham A Rakha,et al.  Estimating Traffic Stream Space Mean Speed and Reliability from Dual- and Single-Loop Detectors , 2005 .

[39]  Hesham Rakha,et al.  Validation of Van Aerde's simplified steadystate car-following and traffic stream model , 2009 .

[40]  Thomas H Maze,et al.  Weather and Its Impact on Urban Freeway Traffic Operations , 2006 .

[41]  Hesham Rakha,et al.  Tool for Calibrating Steady-State Traffic Stream and Car-Following Models , 2007 .