D. Lance Bullard

Development of Hybrid Energy-Absorbing Reusable Terminal for Roadside Safety Applications

The hybrid energy-absorbing reusable terminal (HEART) is a newly developed crash cushion or end terminal to be used in highway safety applications to mitigate injuries to occupants of errant vehicles. HEART is composed of corrugated plates of high-molecular weight, high-density polyethylene (HMW-HDPE) supported on steel diaphragms that slide on a fixed rail. Kinetic energy from errant vehicles is converted to other energy forms through folding and deformation of the HMW-HDPE material. Many previous designs utilized plastic or permanent deformation of plastics or steels to accomplish this goal. However, HEART is a combination of plastic and steel that forms a largely self-restoring and largely reusable crash cushion. Consequently, HEART has a major life-cycle cost advantage over conventional crash cushion designs. HEART was developed through extensive use of finite element analysis with LS-DYNA. The simulation approach adopted for the development of HEART, construction details, and a description and result...

Deception Pass Log Rail in Washington State

Washington State Route 20 (SR-20) in Northwest Washington passes through the Deception Pass State Park. The portion of SR-20 within the park was constructed by the Civilian Conservation Corps (CCC) in the mid-1930s. As part of this work, the CCC built a stone masonry bollard and log rail system to delineate the edge of the road and prevent early-model vehicles from leaving the roadway. Because of their age, quality of workmanship, and importance to the surroundings, the parks bridges and log rail are eligible for the National Register of Historic Places. Previous attempts to replace this rail with a crashworthy system were unsuccessful because of the concern that the aesthetic and historic integrity of the park be preserved. A new approach adopted by the Washington State Department of Transportation began with understanding the context of the highway and the concerns of the other stakeholders. In addition, the stakeholders were educated on the safety issues. As a result, a solution was developed and was acceptable to all. The primary solution involved the development of a new barrier that replicated the appearance of the original log rail. This barrier was crash tested in accordance with NCHRP Report 350 TL-2 criteria and is available for use at other locations at which an aesthetic barrier is desired.