“OF COURSE I had my lights on!” is the familiar cry of the collision victim, but when everything points to the contrary, what techniques can the legal profession employ to discover the truth?
The ‘on or off’ status of a car’s lights prior to a collision can often be cited as a direct cause of the incident, but how can the status of the lamp be proved, particularly if it was damaged in the impact?
The Materials and Engineering Institute’s (MERI) forensic investigation team at Sheffield Hallam University is providing expert witness services for such cases on a regular basis. Working with, and providing training for, the UK constabulary, the team Team profile is helping to determine the causes of major incidents throughout the UK.
A familiar request the investigation unit is used to dealing with is: was the accident caused because the motorcyclist didn’t have his lights on or because the car driver didn’t indicate before turning?
MERI’s forensic team examines various types of light bulbs commonly found in vehicles, including basic incandescent, halogen and instrument panel lamps.
The analysis involves the relationship between manufacturing, operation and failure modes of these types of light bulb.
Failure modes that can be identified include ductile and brittle failures, hightemperature deformation, thermal, oxidation, normal ageing, mechanical and thermal shock failures.