Driver speed behavior on two-lane rural highways in Southern Italy

Numerous studies have been conducted in different countries and on various types of roads to determine, on the basis of the statistic analysis of instrumental direct measurements, the links among the operating speeds and some characteristic parameters of the roads. The objective of this experimental study is to get relationships of general validity for the prediction, in phase of the project, of the speeds that will be used on the infrastructure. The experimental investigation, the object of the present paper, has been conducted employing traffic counters, which are able to record for every vehicular passage in both directions: length, instant speed, and direction of the vehicle. The plan of survey has been elaborated to satisfy different objectives of search (speed in free flow conditions, in entry and in going out of the intersections, in rural to urban transition, etc.) and it has been applied to some roads in the network of the Province of Salerno. The measurements have been performed under observation of each section for 2 or 3 hours. Then the data have been used for starting the formalization of some analytical relationships to predict the operating speeds.