Identifying Low-Volume Road Segments with High Frequencies of Severe Crashes

Low-volume two-lane highways can be characterized by a wide range of physical features. Often the available crash data for these facilities are limited to fatal and injury crash information. It can be a challenge, therefore, to determine whether the select number of severe crashes observed along a corridor merits detailed safety evaluations and the associated investment of limited funds. The technique identified in this paper uses predictive method concepts developed with procedures consistent with those included in the AASHTO Highway Safety Manual but targeted only to low-volume roads and the number of observed fatal and injury crashes. For the purposes of this analysis, safety models are based on detailed crash and site data for low-volume highways in the state of Washington. A simplified procedure is then demonstrated to determine whether the number of severe crashes (fatal and injury) is significant enough to justify a detailed safety assessment and potential special safety enhancements on roadway construction projects or stand-alone safety enhancement projects for low-volume (≤1,000 vehicles per day) rural two-lane highways.