  With rapidly increasing of the land development density along suburban
arterials, much more irregular signal spacing appeared on suburban arterials,
and high access density is commonly observed on suburban arterials. These
issues tend to increase the risk of crash occurrence of arterials. By
developing safety performance functions on road segments and intersections
separately, the previous research analyzed the partial safety effects of the
influence factors. In this study, Bayesian Conditional Autoregressive (CAR)
models were developed at traffic analysis zone (TAZ) level for suburban
arterials laid in suburban area in Shanghai. The model result showed that
higher access and signal density tend to increase crash frequencies occurred on
arterials. At this point, designing frontage roads paralleled to arterials to
collect the access traffic instead of those intensive access could reduce
crashes occurred on arterials.
