The Nebraska Department of Roads, in conjunction with the Federal Highway Administration, has developed a new mailbox support system that could be used to accommodate a wide range of mailbox sizes. To be considered a safe appurtenance, the system had to be subjected to full-scale crash tests, as provided in recommended procedures published by the Transportation Research Board, March 1981. The major concern was to find whether the support system would keep the mailbox attached to the post and would not allow detached elements to penetrate the passenger compartment of a vehicle. Four full-scale crash tests were conducted with an 1,800-pound vehicle. Two tests with the post embedded in weak soil were performed at 20 mph and 60 mph, respectively. Two tests with the post embedded in strong soil were conducted at the same speeds. Three of the tests used a support system that held two mailboxes (size 1-a). One test used a system that supported one mailbox (size 2). After analysing the results of the crash tests, it was evident that all of the performance criteria had been met. The major criteria evaluated were change in velocity (maximum 0.010 Seconds average deceleration), whether the support system kept the mailbox attached to post, and whether the vehicle remained stable and upright during and after the impact.
Samenvatting