As a follow-up to Phases I and II of this project, five rural curves in Delaware County were modified to influence user behavior. Two were given special signing, three special pavement markings: one a widening of the inside edge marking at the curve and one with markings designed to make the roadway appear narrower at the beginning of the curve (Wundt illusion). Both regular road users and test drivers in instrumented vehicles were studied before and after the modifications of the site and thirty days after modification at three positions prior to the curve. Test driver visual search patterns were affected by the pavement markings but not by the special signing. Early curve detection allowed a wider dispersion of fixation. Road user mean speed reductions were noted early for the widened inside edge marker and inter car speed variation was substantially reduced by this treatment although the effect was gone thirty days later, suggesting that ransient rather than local driver behavior would be affected. The Wundt illusion produced speed reductions late (at the beginning of the curve). Signs had little road user effect. What was most obvious was the reduction in the high speeds as a result of the modifications. Author/publisher)
Abstract