The tractor-trailer was carrying a load of cars when it collided with the Caltrans truck and burst into flames.
Fire crews responded quickly, but the big rig and the cars it carried were destroyed.
The big rig driver was injured and transported to the hospital.
The Caltrans workers weren't hurt.
All of the northbound lanes of the 14 except for the carpool lane were closed as crews worked to clear the wreckage off the road.