Study Details

Study Title: Investigating the influence on safety of retrofitting Italian motorways with barriers meeting a new EU standard

Authors: Cafiso et al.

Publication Date:JAN, 2014

Abstract: A new European Union (EU) regulation for safety barriers, which is based on performance, has encouraged agencies to perform an upgrade of the old barriers, with the expectation that there will be safety benefits at the retrofitted sites. The new class of barriers was designed and installed in compliance with the (European Norm) EN 1317 standards for Road Restraint Systems created in 1998, which lays down common requirements for the testing and certification of road restraint systems in all countries of the European Committee for Standardization (CEN). Both the older and new barriers are made of steel and are installed in such a way as to avoid vehicle intrusion, but the older ones are thought to be only effective at low speeds and low angles of impact. The new standard seeks to remedy this by providing better protection at higher speeds. The paper seeks to quantify the effect on the frequency of fatal+injury crashes of retrofitting motorways with barriers meeting the new standards, by performing an empirical Bayes before-after analysis based on data from the A18 Messina-Catania motorway in Italy. The results suggest a safety benefit, which, although statistically insignificant, is enough to recommend that the retrofits are cost-effective and should continue. However, the sample size needs to be increased in order to develop a statistically robust crash modification factor.

Study Citation: Cafiso, S., D'Agostino, C., and Persaud, B., "Investigating the Influence on Safety of Retrofitting Italian Motorways with Barriers Meeting a New EU Standard." Transportation Research Board Annual Meeting, Washington, D.C.,(2014)


CMFs Associated With This Study

Category: Roadside

Countermeasure: Improve guardrail

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.78223 StarsAllK,A,B,CNot specifiedRural
0.67333 StarsRun off roadK,A,B,CNot specifiedRural
0.9823 StarsOtherK,A,B,CNot specifiedRural