Most carriers do not provide GPS tracking to cusotomers directly. It's not a standard industry feature like it is with the mail. Some brokers advertise tracking but no real way to provide it constantly with the hundreds of independent carriers. 

If you have a built in GPS or put an AirTag in the vehicle that is the most reliable option & the driver cannot "opt-out" of that like they often will do with broker platform tracking. If the vehicle is loaded into the trailer it may not transmit reliably, the metal in the trailer may interfear with the signal. 

A customer once called me concerned that her Tesla had not moved from the pickup location in New Jersey- she was furious since it was suppose to arrive in California that day. While she was on the phone with me the carrier pulled up to her home for delivery. They made no other pickups on the way & no reason to start or remove the vehicle from the trailer, meaning the GPS did not update the location as she expected. 

The best way to track is to request an update from your broker. A professional broker will be able to provide an ETA in most cases. Communication is the best tracking possible, which is something that should be prioritized.