Paper presented at the 28th Annual Southern African Transport Conference 6 - 9 July 2009 "Sustainable Transport", CSIR International Convention Centre, Pretoria, South Africa.
Roadside alligators (aka "tire debris") are those unsightly shreds or fragments of rubber that are occasionally found on the roadway. During summer 2007, the University of Michigan Transportation Research lnstitute conducted a national tire debris survey that involved the collection of 39 metric tones of rubber and that provided 300 casings and 1,196 debris items for subsequent failure analysis. This paper presents the tire debris survey methodology, discusses the survey results and shares insights that may be applicable in a Southern African context. Overall, where the original equipment retread status could be determined, there was a 60 I 40 percent split between original equipment (i.e., new) and retread tire casings tested compared to a 21 1 79 percent split for tire fragments. Road hazard or maintenance operational reasons were two of the top three probable damage failure causes. This result suggests that the majority of tire debris items found on U.S. highways is not as a result of manufacturing process deficiencies. The study concludes that it is important for role players in the Southern African transportation industry to explore the lessons learned from the tire debris survey and recommends; firstly, that stakeholders
continue to increase public awareness about the origins, characteristics, and impacts of tyre debris, and, secondly, ensure adherence to the highest standards in vehicle operations and associated tyre maintenance. Resolving these challenges has the potential to see a significant reduction in roadside tyre debris and enhance the road safety environment.
