The Relationship Between Road Accidents and Infrastructure Characteristics of Low-Volume Roads in Israel

This study aimed at the identification of relationships between infrastructure characteristics and accident occurrences, on low-volume non-urban roads in Israel. The low-volume roads were defined as single-carriageway rural roads under the National Transport Infrastructure Company's (NTIC) responsibility, with daily traffic volume below 3,000 vehicles. The study's database included 1358 road sections, with a total length of 1228 km. For each section, accident data and traffic volumes were extracted from the Central Bureau of Statistics' files, while road infrastructure characteristics were produced using the 2010 NTIC road survey's data. Statistical explanatory models were fitted to five accident types including multiple-vehicle collisions, single-vehicle accidents, severe accidents, injury and all accidents. Summarizing the models, it was found that, as expected, an increase in traffic volume leads to an increase in accidents; an initial increase in shoulder width, up to 2-2.5 m, is associated with an increase in accidents, whereas further shoulder widening leads to accident reduction; an initial increase in lane width, up to 3-3.25 m, leads to a reduction in most accident types, where further extension of lane width is associated with an increase in single-vehicle and all accidents. In addition, the increase of minimum horizontal radius is associated with injury accident reduction; the improvement in roadside conditions contributes to a reduction in single-vehicle accidents; vertical grade affects all accidents only, where higher grade is associated with accident increase. Using the models, accident modification factors related to changes in the road infrastructure characteristics were produced. The models developed by the study can serve as a basis for selecting low-volume road section parameters, both during the design and road maintenance processes or black-spot treatment.