You can sometimes use a camera to take the measure\u00a0of important technical issues during a forensic investigation.\u00a0 And unexpectedly get the answers to your questions quickly and easily\u00a0as I found out during one investigation.<\/p>\n
I was retained by the RCMP a few years ago to determine if a pile of\u00a0salt on a highway contributed<\/em> to a fatal motor vehicle accident\u00a0(MVA) – that was the technical issue.\u00a0\u00a0I did this by\u00a0carrying out\u00a0field trials like they do in speed bump\u00a0research.\u00a0 These trials determine the effect<\/em> of different sizes and\u00a0shapes of speed bump on\u00a0vehicles travelling at different speeds.<\/p>\n When I started these trials I didn’t know where they would take me except they approximated what took place during the fatal MVA – and involved measuring like engineers do.\u00a0 There were no neat little formulae, no salt-pile-contribution-determining procedures in text books.\u00a0\u00a0But I had to\u00a0start somewhere – the way it so often is in forensic engineering investigation.\u00a0 The end result was surprising in answering the question about the contribution of the salt pile.<\/p>\n I built\u00a0a test site on\u00a0a run way at the Shearwater airport\u00a0like those for speed bump research.\u00a0 I\u00a0marked off a\u00a0traffic lane on the runway\u00a0the same size as that at the accident scene.by painting a centre\u00a0line and shoulder lines.\u00a0 I then constructed a pile of salt in the lane the same shape and size as that at the scene.\u00a0\u00a0My tests would involve driving the vehicle in this lane, over the pile of salt and filming what happens – the effect.<\/p>\n Speed bump research records what happens to a vehicle at\u00a0a speed bump by measuring and photographing its position\u00a0in three dimensions:<\/p>\n I did the same at my test site.\u00a0 The painted traffic lines oriented the vehicle side to side in the lane.\u00a0 A large ruler consisting of\u00a01.0 foot\u00a0graduations painted on the asphalt down the lane from the salt pile located the vehicle in that direction.\u00a0 Another ruler consisting of 0.5 graduations marked on a sheet of plywood set at the\u00a0side of the lane opposite the salt pile located the vehicle vertically.<\/p>\n I retained three professional photographers to film the position of the vehicle as I drove over the pile of salt.<\/p>\n I also staged the position of the vehicle on the salt pile and had this filmed from a sea king helicopter for illustrative purposes – you would use a drone fitted with a camera to get these pictures today.\u00a0 The photographer with his camera is shown above in my blog site masthead.<\/p>\n The RCMP told me that the vehicle was travelling at a speed of 50 km\/hr or more when it hit\u00a0the pile of salt. \u00a0This was based on tests by their accident reconstruction specialist.\u00a0 I planned to\u00a0do\u00a0my test at that speed but start at\u00a0the lower speed of 20 km\/hr and gradually increase.<\/p>\n I drove the vehicle over the pile of salt at\u00a020 km\/hr\u00a0as the cameras rolled.\u00a0 It was pretty well all I could do to keep the vehicle in the lane after striking the pile of salt – it did veer off to the right a little and this was captured by the camera man in the boom truck.\u00a0 Striking<\/em> is an apt term.\u00a0 And it was all the camera man in the cab with me could do to keep his camera steady as the vehicle rocked and rolled.<\/p>\n We saw on viewing film of the vehicle against the backdrop of the big rulers that\u00a0the vehicle\u00a0got 2.0 feet of air on striking the pile of salt and the front wheels stayed aloft for 18 feet before landing on the test lane again.<\/p>\n The three cameras recorded about 30 minutes of film.\u00a0 I viewed this film and\u00a0edited it to a four minute film clip to include in a\u00a0preliminary report to the RCMP.\u00a0 I reported that I could not continue the testing at higher speeds until I had safety and rescue procedures in place for the driver.<\/p>\n The RCMP and\u00a0counsel on viewing the film clip and learning\u00a0of\u00a0my need for safety measures stopped all further testing. \u00a0“No need to continue testing, we have our answer”.<\/p>\n They quickly saw in the film clip the effect,\u00a0the contribution <\/em>of\u00a0<\/em>the pile of salt to the erratic behaviour of the vehicle and\u00a0its airborne\u00a0trajectory at 20 km\/hr. \u00a0It didn’t take much imagination to know\u00a0how the pile of salt would contribute to a fatal\u00a0MVA at\u00a0a speed of 50 km\/hr.\u00a0 Seeing\u00a0is believing when you’re taking the measure of some things. \u00a0That’s often more than good enough for the justice system.<\/p>\n But\u00a0all of this was also quantified by filming and recording the 2.0 foot and 18 foot airborne measurements and the veering of the vehicle off to the side of the traffic lane.<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" You can sometimes use a camera to take the measure\u00a0of important technical issues during a forensic investigation.\u00a0 And unexpectedly get the answers to your questions quickly and easily\u00a0as I found out during one investigation. I was retained by the RCMP … Continue reading \n
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