It is known that pavement edge (vertical) drop-offs, ranging in height from two inches to five inches, are frequently observed at the pavement edge on two-lane rural roadways. When an errant vehicle leaves the edge of the traveled path and encounters a pavement edge drop-off, it may be difficult for the driver to negotiate the drop-off and safely return to the traveled way. There is potential for the tire to scrape along the drop-off instead of being able to negotiate safely back into the traveled way. This unexpected tire engagement and corresponding resistance often leads to driver over-correction, directing the vehicle to return to the roadway at a sharper angle than necessary. On narrow two-lane roadways, this can result in the vehicle encroaching into the opposite lane of traffic and being involved in a secondary collision. This secondary collision can take the form of a (1) head-on collision with the opposing lane traffic, (2) sideswipe collision with the opposing lane traffic, (3) a run-off-road crash on the opposite side of the road, or (4) an overturn either within the traveled way or on the opposite side of the roadway. One pavement edge solution being used by some states, particularly when a pavement overlay is applied, is the termination of the pavement edge at a sloped angle, creating a fillet rather than a vertical edge. Prior research tends to indicate that the edge fillet, currently termed the "safety edge" or "edge wedge," presents less resistance to vehicle tires and can lead to a smoother, more controlled reentry back into the traveled way. Further evaluation is needed on the safety edge to determine its effectiveness.

The goal of the proposed research is to evaluate the effectiveness of using the Safety Edge (edge wedge) to help prevent and reduce severity of pavement edge drop-off related crashes. A before-after evaluation (Empirical Bayes method) will be performed on sites with upcoming installations of the safety edge in the U.S.

The initial scope of the Safety Edge Pooled Funds Study is to conduct a research project totaling $500,000 over three years. The end results will be an Empirical Bayes evaluation, using before-after data (where safety edges are installed), to help determine their effectiveness in reducing the number and severity of crashes due to pavement edge drop-offs. A contractor will be hired to collect before data (crash, traffic and roadway) this early summer (2004) at each of the sites where states believe they will be installing the safety edge. Once installation is complete, data will be collected and used to help determine the effectiveness in reducing crash frequency and severity. This construction season at least eight states are planning to install safety edges; it is our intent to collect data from each of these states, where appropriate sites and data are available. FHWA is spending $150,000 of FY 04 safety research funds to help begin the collection of data due to the rapid timeframe.

Solicitations will continue to be accepted through August 31, 2004. States interested in joining the study should contact Ms. Lisa Williams at (202) 493-3376. This project is open to any number of participating states, with a minimum of 5 states. The approximate amount of funding requested per state is $15,000 per year for 3 years. Total anticipated state funds are $225,000 over 3 years. FHWA will contribute $275,000.