Transportation Research Record Journal of the Transportation Research Board · 2015 · 36 citations · 5 references
PlanningTransportation PlanningUrban PlanningTransportTransport PlanningTransportationPublic TransitTraffic Impact AssessmentTransport ModellingTransportation-land Use IntegrationUrban MobilityUrban TransportGeographic Information System DataHousehold Surveys MethodologyHousehold Travel SurveysImpactsLand Use Transport ModelingLand Use-transport Interaction ModelsTraffic Impact AnalysisTraffic Impact Mitigation
Current traffic impact analysis methods underestimate the benefits of mixed‑use developments, leading to unnecessarily high exactions and discouraging desirable projects. This study aims to develop a more accurate methodology for predicting the traffic impacts of mixed‑use developments. Using standard protocols, the authors identified MXDs in 13 metropolitan regions, pooled household travel survey and GIS data, defined travel and built‑environment variables consistently, and applied hierarchical modeling to estimate internal trip capture and external walking, biking, and transit use. MXDs with diverse on‑site activities captured a large share of trips internally, reducing their traffic impacts compared to conventional suburban developments, while smaller walkable MXDs with good transit access generated significant walk, bike, and transit trips, further mitigating traffic impacts.
Current methods of traffic impact analysis, which rely on rates and adjustments from ITE, are believed to understate the traffic benefits of mixed-use developments (MXDs) and therefore to lead to higher exactions and development fees than necessary and to discourage otherwise desirable developments. The purpose of this study was to improve methodology for predicting the traffic impacts of MXDs. Standard protocols were used to identify and generate data sets for MXDs in 13 large and diverse metropolitan regions. Data from household travel surveys and geographic information system databases were pooled for these MXDs, and travel and built-environment variables were consistently defined across regions. Hierarchical modeling was used to estimate models for internal capture of trips within MXDs and for walking, biking, and transit use on external trips. MXDs with diverse activities on site were shown to capture a large share of trips internally, so that the traffic impacts of the MXDs were reduced relative to conventional suburban developments. Smaller MXDs in walkable areas with good transit access generated significant shares of walk, bike, and transit trips and thus also mitigated traffic impacts.
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Travel and the Built Environment
Reid Ewing, Robert Cervero · Journal of the American Planning Association · 2010 · 5.1K citations