Impact of road-surface condition on rural highway safety: A multivariate random parameters negative binomial approach

摘要: Abstract Recent studies have begun to shed more light on the crashes experienced rural roads by examining influence of a road’s pavement surface condition. In bid contribute this growing body knowledge and facilitate comprehensive evaluation maintenance projects, paper explores safety effects condition roads. The tests hypotheses that roughness generally has non-trivial residual impact outcomes magnitude direction these impacts differ across road segments. To explore hypotheses, presents crash frequency models for three levels severity also five developed use multivariate random parameters negative binomial specification account unobserved heterogeneity correlation among different severity. model results suggest pavements in fair or good condition, parameter fixed frequency, irrespective level. However, poor variable significant is normally distributed. positive portions density function higher (poorer condition) increases expected likely because drivers may lose control their vehicles. within range, associated with lower are drive carefully very (a manifestation risk-compensation behavior). can help highway engineers quantify not only benefits resurfacing projects but consequences worsening conditions arising from delay maintenance.