In 1981, the Nevada highway Department conducted some astonishing crash tests of four Captive Column light pole prototypes. These tests consisted of running a car into four poles at two speeds, 20 mph and 40 mph, using slip bases and fixed bases. These tests were filmed with high-speed camera equipment and the results were spectacular. The lower section of the Captive Columns broke away clean at the base and traveled with the vehicle, sliding up and over the hood. The same car was used in all four tests because the damage was limited to scratches and small dents. In some cases the crew had trouble finding the scratches and had to circle them with a wax pencil so they could be located in photos.
These Captive Column light poles were so safe that it was possible they could even save lives in a sideswipe accident. They met all ballast and wind load requirements for a light pole, yet they were so light that a downed pole could easily be moved by hand to get traffic moving again. This level of safety actually presented a problem that had never been faced before -- the poles would need to be beefed up so that they would inflict some damage to prevent marauding teenagers from knocking them down for kicks. Captive Columns can easily be beefed up; it's simply a matter of selecting the proper materials to fit the needs of the application.
Design News did a story on the Crash Tests in its August 4, 1980 issue but did not acknowledge Mr. Bosch in the article.
You can get a copy of this study from the National Technical Information Service in Springfield, Virginia 22161. Ask for Report Number FHWA/RD-81/501.
Copyright © 1998-2004 by Lawrence R. Bosch.