Examining the relationship between community design and crash incidence.

456225700PDFTech Reporthttp://ntl.bts.gov/lib/31000/31100/31174/167173-1.pdfSWUTC/09/167173-110727Traffic safetyCity planningUrban designLand useTransportation planningLand use planningPlanning methodsStrategic planningSan Antonio (Texas)Texas Transportation InstituteDumbaugh, EricRae, RobertWunneberger, DouglasTexas Transportation InstituteSouthwest Region University Transportation Center (U.S.)US Transportation CollectionThis study seeks to understand how urban form\ue2\u20ac\u201dspecifically land use and street network configurations\ue2\u20ac\u201dmay influence the incidence of traffic-related crashes injuries and deaths. It begins with an historicoverview of the safety concepts that directed community design practice during the 20th century and detailshow these design concepts transformed themselves into contemporary community design practice. It detailsthe development of a database of crash incidence and urban form at the block group level for the City ofSan Antonio, the first such database of its kind. Data acquired from this database are then modeled usingnegative binomial regression models to determine how urban form may be associated with the incidence oftraffic-related crashes, injuries, and deaths at the block group level. It finds that the presence of arterialthoroughfares, strip commercial uses, and big box stores are significantly related with increased crash risk,while the presence of more traditional, pedestrian-scaled retail configurations are associated with areduction in crash incidence. The population density of a block group was similarly associated with areduction in crash incidence. Intersections had a mixed effect, reducing fatal crashes, but at least in the caseof 4-leg intersections, also increasing the incidence of total and injurious crashes. Based on these findings,this study discusses the implications for design practice and outlines three strategies for enhancing trafficsafety through community design