Last week's answer

Question: Driving a traditional Truck-Mounted Attenuator (TMA) "shadow truck" behind mobile patching or striping crews is one of the most hazardous jobs in highway maintenance. To protect operators, several state DOTs have deployed driverless Autonomous Truck-Mounted Attenuators (ATMA). How does an unmanned follower truck accurately mirror the speed, steering path, and braking of the lead crew vehicle in real time?

Answer: By using a short-range Leader-Follower vehicle-to-vehicle (V2V) telemetry link combined with high-precision RTK-GPS to execute the leader's exact path coordinates.

The lead vehicle is operated by a human driver that is continuously transmitting highly accurate speed, position and heading information to the ATMA, so it can replicate the lead vehicle's path. The ATMA will maintain a specified gap distance that is set by the human operator of the lead vehicle. 

Sources: AASHTO