Cost-benefit analysis of road safety measures

Road accidents represent one of the most serious problems faced by the Ministries of Public Health in the World. In Italy for example, in the year 2007 there were almost 330,000 injuries and 5,131 fatalities; 230,871 crashes in all which resulted in an estimated € 30.4 billion financial loss, corresponding to 2% of GDP. In 1999 the National Road Safety Plan (NRSP), among other things, funded the requalification of several unsafe road infrastructures at higher risk of accidents. Unlike other infrastructure investment plans, NRSP usually requires: i) specific safety analysis of crash history to identify the critical road; ii) proactive action, e.g. RSAs and RSARs; iii) before-after accident study; iv) ex-post monitoring of road user behaviors, etc. The paper presents some unsafe roads in urban and suburban areas which were renovated through NRSP strategies and whose projects were submitted to Road Safety Audit procedure for black spot treatment. It examines the effect of physical traffic calming measures (e.g. roundabouts) on accident risk and user behaviours: ante- and post-operam evaluations are compared on the basis of accident data and investigations in situ (particularly traffic flow and operating speed). Finally, a profitability analysis of several parameters (e.g. accident social costs) is performed. In a region like Sicily, the first Road Administration investments on unsafe infrastructures, partially funded by NPRS, have shown very positive results as to safety and financial aspects.