A reflexive reaction, when driving an automobile, to a sudden obstacle or condition outside the car. The reaction can take the form of ducking one's head, swerving one's body to the side, or otherwise moving one's body. The reaction does not affect the steering or direction of the car, however. The reaction is typically irrational, given that the outside obstacle does not truly threaten the vehicle passengers.
* When driving near the airport runway, I car flinched when an airplane came in for landing over our heads.
* I car flinched last night when a bird suddenly flew towards the front of my car.