How fast was he driving when he hit the girl on the sidewalk?\u00a0 He’s dead now after falling asleep at the wheel, hitting the\u00a0girl then hitting a\u00a0pole.\u00a0 So’s the girl after sliding several metres in the grass.\u00a0 Speed is important in reconstructing an accident like this.<\/p>\n
His speed can be assessed from the damage to his car.\u00a0 It’s called a “crush” analysis, not surprisingly.\u00a0\u00a0The assessment\u00a0can be cross-checked with a\u00a0different\u00a0analysis using data from the skid marks of the girl in the grass.<\/p>\n
Experts in accident investigation like to cross-check assessments like these – and also refine the analytical methods with new data.\u00a0 Some of the methods are rough and seemingly not very scientific but\u00a0that’s hands-on engineering and better than nothing.\u00a0 If you can measure something – e.g., skid marks, crush shape –\u00a0even approximately, you can “manage” it; in this case get the speed of the car.<\/p>\n
That’s what I was doing\u00a0last week at a meeting in Moncton of CATAIR, taking part with about\u00a0eight others collecting data for the continued refinement\u00a0of an analytical technique.\u00a0 This time using the skid marks of a body in the grass for determining the speed of a vehicle during an accident.\u00a0 It sounds complicated but a lot of it boils down to determining the coefficient of friction of a surface\u00a0like in simple high school physics.<\/p>\n
With enough testing, chaps like Mike Reade, Moncton\u00a0hope results will benefit investigators\u00a0in situations when they\u00a0only know the pedestrian’s sliding\/tumbling distance after an accident.\u00a0 The results will be shared with\u00a0others who\u00a0work in this field. (Refs 1, 2)<\/p>\n
In this case, Mike, who was directing the research and will crunch the data later, threw Skippy, a full size dummy, from a speeding pickup truck driven by Ken Zwicker, Bridgewater.\u00a0 The rest of us carried out various tasks like spotting where Skippy hit the\u00a0ground, measuring how far he slid and videotaping what happened to him after he was “hit” by the truck.\u00a0 Katelynn Everett, a consulting professional engineer from Fredericton, recorded data and did\u00a0preliminary number crunching.<\/p>\n
The field trials are part of the very impressive, ongoing work by CATAIR, the Canadian Association of Technical Accident Investigators and Reconstructionists,\u00a0and others to refine the analytical methods used by traffic accident investigators.\u00a0(Refs\u00a02 to 7)<\/p>\n
The association is a mix of serving and\u00a0former RCMP and municipal police officers, professional engineers and technologists all of whom are interested\u00a0in\u00a0traffic accident investigation and reconstruction.<\/p>\n
In the morning before starting the field trials we met and discussed about 12 different courses on topics related to traffic accident investigation that are available to CATAIR members.<\/p>\n
CATAIR\u00a0meets somewhere in the Atlantic provinces\u00a0about three or four times a year and\u00a0do field tests\u00a0most times.\u00a0\u00a0Recently\u00a0three teams measured the crushed shape of three different cars\u00a0that had been involved in\u00a0traffic accidents.\u00a0 Each team is analysing speed using different methods and comparing\u00a0results – Stu Smith, Dartmouth gave a brief report\u00a0at the meeting\u00a0on his work on this.\u00a0 Another time the stopping distance of a vehicle on a road was measured.\u00a0 And another time still, the turning radius\u00a0and\u00a0the path of\u00a0the rear wheels of a school bus were measured.<\/p>\n
Nobody gets paid for this field research.\u00a0 It’s all to do with refining our understanding of the cause of traffic accidents and reconstructing these, and the camaraderie\u00a0of like-minded people working together – we do have fun when we’re getting our hands dirty\u00a0and mud on our boots.<\/p>\n
References<\/strong><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" How fast was he driving when he hit the girl on the sidewalk?\u00a0 He’s dead now after falling asleep at the wheel, hitting the\u00a0girl then hitting a\u00a0pole.\u00a0 So’s the girl after sliding several metres in the grass.\u00a0 Speed is important … Continue reading \n