IMAGE

1

Current methods of traffic impact analysis are believed to understate the traffic benefits of mixed-use developments (MXDs) and potentially overstate potential roadway impacts because they don’t fully account for the interactions between land uses or the surrounding built environment. A national study for the US EPA, performed by a team composed of Fehr & Peers and the University of Utah, developed a new methodology to
more accurately predict the traffic impacts of MXDs. The study found that MXDs reduce traffic impacts, relative to single-use suburban development, due to the following key factors.
- Diverse on-site activities that capture a large share of trips internally.
- Placement within walkable areas with good transit access that generate high shares of walk and transit trips.
- Central locations that reduce trip lengths.
The potential vehicle trip reductions from MXDs were significant enough to demonstrate that conventional trip generation methods could exaggerate roadway impacts and the need for mitigation including higher impact fees, exactions, and negotiated payments than should be the case. These factors could also contribute to potentially discouraging
development of otherwise desirable projects.