An intelligent turn signal control system for turning on and off left and right turn signals in a vehicle. The system includes a computer, such as an antilock braking system computer, with programmed software operably disposed on a vehicle, and a driver interface switch assembly as input to the computer. Sensors transmit angle, differential wheel movement or related data as input to the computer, while a circuit drives turn signal indicator lamps from conditionally computed output data from the computer to turn on and off turn signals in a situation-appropriate manner. Upon turn signal indication intent data input from the driver, extensive travel and turn data is computed, including yaw rotation and steering system position to turn off or cancel the turn signal at the appropriate point.