Using Travel Demand Model and Zonal Safety Planning Model for Safety Benefit Estimation in Project Evaluation

The Federal Highway Administration (FHWA) has been promoting transportation safety planning which requires a forecast of crashes in the future. This study describes a modeling approach for planning-level zonal crash prediction model development and application. First, different categories of factors from the ample data source of the regional travel demand model are identified by using geographic information system functions. These factors are used to develop a planning-level crash estimation model using negative binomial regression analysis. Following this, the safety benefits for two transportation planning projects were estimated by applying this model in combination with the travel demand model from a region-wide perspective. The results suggest that the modeling framework seems a justified approach in estimating future crashes and project safety benefits with certain assumptions, which may fill the gaps in current planning-level project evaluation by explicitly considering future safety.