Pre-existing motor vehicle defects or maintenance conditions that may have contributed to the crash.
Subfield 1: Motor Vehicle Circumstance 1:
Lights (head, signal, tail)
Truck Coupling / Trailer Hitch / Safety Chains
Subfield 2: Motor Vehicle Circumstance 2:
Important for determining the significance of pre-existing problems, including equipment and operation, in motor vehicles involved in crashes that could be useful in determining the need for improvements in manufacturing and consumer alerts.