Since shortly after the first automobiles rolled off an assembly line, guardrails, bridge rails, crash cushions, and other safety devices have been installed on roadways in an effort to improve the safety of the traveling public. Just as automotive safety design has improved tremendously over the years, the design and application of roadside safety appurtenances has improved vastly as well. State Highway Departments and the Federal Highway Administration were the original driving force behind many of these safety improvements, but over the last 30 years or so private industry has provided much of the innovation that has led to products which make the roads safer. This is especially true with guardrail terminals.
The purpose of a guardrail is to shield motorists from natural or man-made obstacles located along either side of a traveled way. An impact with a guardrail system should prevent contact with the hazard being shielded, and be less severe than an impact with that hazard. A typical guardrail system is anchored on both ends, and when an errant vehicle impacts along the length of guardrail, tension is developed in the rail and the vehicle is redirected away from the hazard. The ends of the guardrail system are potential problem locations, as a vehicle impacting an untreated guardrail end can be stopped abruptly resulting in high deceleration forces for the occupant, or the guardrail could penetrate the occupant compartment and cause serious injury. In the early days these guardrail ends were left untreated, resulting in many vehicles being ‘speared’ with the guardrail during a collision.
Guardrail “Terminals” were eventually developed to improve the impact performance of the ends of the guardrail systems. These terminals started out as basic as twisting the guardrails and anchoring it at ground level, and have evolved over the years to sophisticated “energy absorbing” terminals which capture the errant vehicle and bring it to a controlled stop. The technology used for many of these modern guardrail terminals is proprietary, and are only available for purchase from the company owning rights to the patents.
Having worked for ten years designing and crash testing roadside safety appurtenances, Dr. Brian Pfeifer had the opportunity to lead the development of several of these lifesaving designs, and has seen first-hand the difference that this technology can make in the dynamics of a collision. Of course, guardrails and guardrail terminals cannot be designed to safely bring vehicles to a stop under every impact condition, but they must be crash tested under specified impact conditions and approved for use by the Federal Highway Administration before they can be used in any projects using federal funds (a large majority of roadway projects receive at least some amount of federal funding).Even with all of this improved safety technology, people die as a result of impacts with guardrail terminals every day. Some of these deaths are the result of extreme or unusual impact conditions, but many are the result of poor product design, improper terminal selection, or faulty installation. If you have a case that involves these issues, it is very important to understand the role that the safety device played. In order to understand these issues, it is important to involve an expert familiar with the design and operation of roadside safety devices early on in your investigation.
Please contact Brian Pfeifer, Ph.D., P.E. and our team of engineers and technicians and put our experience and expertise to work for you.