Abstract
The physical protection afforded by crash barriers is rather well known. The present paper submits that such barriers could also have important favorable effects on the behavior of drivers from the standpoint of highway safety, at least when the crash barrier is installed in the proximity of the traffic flow. Three different categories of such behavioral influence are described, and the available evidence concerning each of them is briefly reviewed and discussed. Finally, a possible extension of the use of the crash barrier—specifically its installation along the mid-line of broad two-lane roads—is proposed for further investigation.