Since the mid-1980s, limited use has been made of vehicle tracking using satellite communications to mitigate the security and safety risks created by the highway transportation of certain types of hazardous materials. However, vehicle-tracking technology applied to safety and security is increasingly being researched and piloted, and it has been the subject of several government reports and legislative mandates. At the same time, the motor carrier industry has been investing in and implementing vehicle tracking, for a number of reasons, particularly the increase in efficiency achieved through better management of both personnel (drivers) and assets (trucks or, as they are known, tractors; cargo loads; and trailers). While vehicle tracking and immobilization technologies can play a significant role in preventing truck-borne hazardous materials from being used as weapons against key targets, they are not a silver bullet. However, the experience of DTTS and the FMCSA and TSA pilot projects indicates that when these technologies are combined with other security measures, and when the information they provide is used in conjunction with information supplied outside of the tracking system, they can provide defensive value to any effort to protect assets from attacks using hazmat as a weapon. This report is a sister publication to MTI Report 09-03, Potential Terrorist Uses of Highway-Borne Hazardous Materials. That publication was created in response to the Department of Homeland Securitys request that the Mineta Transportation Institutes National Transportation Security Center of Excellence provide research and insights regarding the security risks created by the highway transportation of hazardous materials.