Collision
Scene Photos Objective: To recreate the position of the sun in the viewfield of a driver in the moments prior to a collision. Background: An eastbound fuel tanker truck collided with the rear of a school bus stopped at a pick-up location on an early December morning. The sun's low position in the eastern sky blinded the truck driver as he negotiated a sweeping right turn, from eastbound to south-east-bound, on an 80 kph stretch of highway. The turn brought the stationary bus directly in line with the sun, which was momentarily shielded by a large pine tree. As the sun "re-appeared" from behind the tree, the sun and bus were directly in line. Shade from an existing forest contributed to a prolonged icy glaze over the highway in the vicinity of the bus. Evasive action by the truck driver was delayed due to visibility conditions (i.e. sun blinding) and hampered due to road conditions (i.e. icy glaze on the shaded portion of highway). Methodolgy: The two photos below demonstrate how the scene was re-created from the vantage point of the truck driver. They are samples of a series of 13 that were taken at the collision scene. The photos were taken at the driver's eye height in 100-foot intervals along the highway prior to the point of impact (POI). The location of the school bus was determined from the police collision report. The collision scene was surveyed using total station survey equipment. From this survey data, a 3D computer model of the terrain was generated into which the sun's position was inserted using software developed by R. Bouwmeester & Associates. The next step involved creating "driver's eye perspective views" within the 3D model. These views were created to match the driver's vantage point as depicted in each of the photos taken at the 100-foot stations. In the final step we superimposed the computer-generated wire-frame perspective views into each of the photos. Two samples, depicting the views at 800 feet and 400 feet prior to impact, are shown. Outcome: All charges against the truck driver were dropped. 
STA 800 - 800 feet from POI (school bus is depicted in yellow wire-frame only)
STA 400 - 400 feet from POI (school bus is depicted in yellow wire-frame only) Ralph Bouwmeester, P. Eng.
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