Effects of Neighborhood Street Patterns on Traffic Collision Frequency

Over the last 50 years, the loops and lollipop design has become the basic building block of many urban neighborhoods. In the field of traffic engineering, this combination of cul-de-sacs and loop streets is designed to discourage through traffic and improve road safety and thus has the support of many traffic engineers. Perhaps due to its intuitive appeal, few studies were conducted to examine the impact of this design on road crashes. Using the City of Calgary in Canada as a case study, this study examines the effects of different neighborhood street patterns on the number of reported crashes. Our results suggest that currently popular road patterns such as warped parallel, loops and lollipops, lollipops on a stick, and mixed shapes are associated with fewer crashes than traditional gridiron pattern.