Using safe systems approach to assess traffic impact and land development [R35]

Traffic impact analysis (TIA) is an important piece of how our transportation system is planned, designed, and built. Cities and states use TIAs to assess how road users currently use the transportation system and then predict how the system will operate if transportation patterns change through the addition of new buildings within an area or through new capacity added to the roadway. Many local and state governments view the TIA process as a critical means of generating needed infrastructure improvements, and its use has become ubiquitous among DOTs across the US. TIA can therefore exert a powerful influence on urban land use and transportation systems. However, little attention has been paid in research or in current practices to TIA’s direct impacts on road safety or its potential role in shaping safe systems. This is somewhat surprising, given TIA’s conventional deployment as a means to minimize and mitigate the traffic congestion impacts of new development by tying roadway capacity improvements to land development permits. This project addresses this gap by (1) evaluating whether, how, and the extent to which current TIA practices incorporate safety into assessments of impacts of land development or into strategies to mitigate those impacts, (2) identifying opportunities to integrate safe systems concepts and metrics into the development review process, and (3) advancing a new, safe systems-approach to estimating and minimizing the safety impacts of new land development.