Well, it depends on what frequencies that tracking device use for positioning your location. Some old model gps tracking devices use only gps satellite signal for positioning. Yet, most of nowadays gps tracking devices not only use gps signal but also gsm to send real time data to its dispatch.
I had a black box installed into my car by the insurance company, I bought a gsm gprs gps jammer as suggested by the seller to completely block that fuck black box. It's similar to this one, just for your reference: