Supersonic Ground Vehicles

Greetings:I just loaded for the first time Malpensa (LIMC) from ISD Project. Was so impressed that I also loaded Linate (LIML). Truly exceptionally well done sceneries. However, is there any way to slow down the ground vehicles that run the perimeter of the airports? At times, their speeds exceed takeoff of the Ai jets! Just wondering if their speeds are tied to the simulation rate or is there a specific file that can be altered to slow these vehicles to more realistic speeds? This is also true for the "tugs" that run at Fly Tampa's (freeware) Boston's Logan (KBOS). ThanksChris