Was the turn signal activated prior to collision?

Post-accident lamp examination by an accident reconstructionist can prove whether the driver activated the turn signal.

You are slowing in traffic to make a left turn. You have activated your left turn signal. The inattentive driver behind you slams into the rear of your vehicle. At the scene, the investigating officer asks for your version and the other driver’s version. The other driver tells the officer you did not have your left turn signal activated and you made a sudden stop without warning. An examination of the turn signal bulb will usually prove the existence of electrical flow at the time of impact. Most automotive bulbs have filaments made of tungsten steel; the filament reaches a temperature of approximately 4,000 degrees thereby giving off light. If the impact was severe enough to fracture the bulb, oxygen would cause the filament to quickly oxidize. Consequently, close examination would reveal the presence of tungsten oxide and/or a blackened filament. If the impact did not cause the bulb to fracture, the super-heated tungsten would be very pliable and would likely deform or change shape as a result of the impact. Therefore, you have scientific proof that the turn signal was activated prior to collision.