Quantifying weather impacts on traffic operations for implementation into a travel time reliability model

Abstract

Travel time reliability allows agencies to evaluate the performance of a facility beyond the peak hour, and to consider operations over a longer period of time considering non-recurring events, such as incidents and adverse weather. The Florida Department of Transportation (FDOT) has incorporated travel time reliability as a primary mobility performance measure. This paper details the method developed for addressing the effects of weather on travel time, as well as its implementation on travel time reliability estimation for state-wide reporting in Florida. To account for Florida-specific conditions, weather impacts focus only on rain intensity. The methodology incorporates different rainfall characteristics of regions across Florida and calibrates the rainfall intensity distribution models on a zip code basis for each hour. The probability of clear weather, light rain, and heavy rain is determined for each hour and then applied to the respective freeway or arterial section based on its zip code.

Keywords:

• Rain intensity distribution
• Travel time reliability
• Weather impact
• Traffic operations