The collision took place in a busy street in London, and involved a left hand drive, rigid large goods vehicle and a pedestrian crossing the road at a zebra crossing from the driver’s right hand side (i.e. across the cab given the driver’s seat position). Unusually, the pedestrian was struck on the left front corner of the truck, meaning that she had crossed the majority of the carriageway before the fatal impact.

In order to get the investigation underway the expert decided to take the following course by investigating: time taken for the lady (a pensioner) to cross to the point of impact, the conspicuity of the pedestrian, given that a slower moving object in the peripheral vision is much less obvious, time taken to slow the vehicle at its weight at the time of collision from various speeds, the sight lines from the vehicle across the cab given the driver’s weight (the adjustable, air ride seat found in such trucks sinks when the driver’s weight is applied), any other vehicle defect which might have caused it to perform below its normal standard, whether the driver was within his tacograph limits, as fatigue is key in the loss of awareness, and a thorough read of the Police Collision Investigator’s report to establish whether they had considered all the factors.

In order to complete this investigation, the consultant had to travel to France to view the vehicle as well as visit the site of the collision.

His examination of the vehicle concluded that the the driver would have had a better view of the point of impact the further he was from it. Given that microscope analysis of the tacograph identified a speed of not in excess of 23mph, and that the consultant was able to calculate deceleration rates under braking, he was able to piece together what was in view from the point where the pedestrian stepped from the pavement to her impact with the vehicle. In order to explain the complexities of road traffic accident investigation to a jury, the various elements were pieced together in the form of a report, plan, photo album and DVD video footage.

It was concluded that a mistake on the part of the driver had caused the accident in which the old lady died. The exact cause of the driver's lack of awareness will be known only to him. From the legal point of view, they were able to advise that he was unlikely to be able to construct a reasonable defence and the insurance company were advised accordingly.

What then does this tell us about the world of the collision investigator?

At the very least it shows what a varied and complex role it can be. In our day to day lives we do not concern ourselves with the mechanics of how these kind of investigations work behind the scenes, yet upon examination it proves to be fascinating.