CRASH TESTS OF MINNESOTA MAILBOX SUPPORTS

In Minnesota snow presents a special problem for rural mailbox installations. So, Minnesota Department of Transportation (Mn/DOT) developed cantilevered mailbox support designs. Recent studies had shown that certain rural mailbox installations easily penetrated the passenger compartment of an impacting vehicle. These same studies pointed out that a large number of people are seriously injured or killed each year as a result of mailbox collisions. Therefore, Mn/DOT initiated full scale crash test to assertain the crashworthiness of its cantilevered design. The study results were: 1. The change in vehicle momentum was below the recommended limit. 2. The test vehicle remained upright with no tendency to spin out or roll over. (The four by four wood vertical support was not hit. Studies by others adequately document vehicle/post interaction). 3. The windshield was broken in each test. However, no part of the test article penetrated into the passenger compartment. 4. There was no appreciable difference between the support designs. The study concluded that the Mn/DOT cantilevered designs are acceptable in terms of nationally recognized criteria. Some precautions are also given as to use and placement of the supports. (FHWA)