The TC-31A is an automated version of the TC-31 Truck Entrance sign. These signs warn drivers when a slow moving truck is exiting a roadside work zone allowing them to slow down or move over to make room. The standard TC-31 sign has been found to be very ineffective due to the infrequency of trucks exiting a work zone, drivers get used to the sign and begin ignoring it. The TC-31A adds vehicle detection at the truck exit as well as wireless activation of warning beacons at the sign itself. The sign is also accompanied by a When Flashing sign so that drivers know that the system is remotely activated. This improvement has been found to be incredibly effective. The system is designed such that upon activation the flashing lights will blink with an MUTCDC 50/50 wig-wag pattern for 1 minute.