Abstract
Community severance occurs where road traffic (speed or volume) inhibits access to goods, services, or people. Appleyard and Lintell's seminal study of residents of three urban streets in San Francisco found an inverse relationship between traffic and social contacts. The extent of social networks predicts unhealthy behaviors, poor health, and mortality; high rather than low social integration is associated with reduced mortality, with an effect size of similar magnitude to stopping smoking. Although community severance diminishes social contacts, the implications of community severance for morbidity and mortality have not been empirically established. Based on a systematic literature search, we discuss what is actually known about community severance. There is empirical evidence that traffic speed and volume reduces physical activity, social contacts, children's play, and access to goods and services. However, no studies have investigated mental or physical health outcomes in relation to community severance. While not designed specifically to do so, recent developments in road design may also ameliorate community severance.