Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer

A motorcycle crashed into the side of a school bus (bus 1), which was turning left from a side street onto the main thoroughfare where the motorcycle was traveling. Video from the bus interior shows children jostled from their seats as a result of the impact.

Another school bus, (bus 2) uninvolved in the subject incident, was also traveling on the main thoroughfare. Bus 2 was equipped with a digital video recorder designed for monitoring buses, capturing the sight and sound of a motorcycle passing by shortly before impact. Seconds after the motorcycle passed bus 2, the driver of bus 1 is heard reporting the incident over CB radio, on the audio of bus 2’s recording.

The audio and visual data extracted from bus 2’s video was utilized to establish several key timelines, including the time elapsed between when the motorcycle passed by bus 2 to when the driver of bus 1’s report of the collision transmitted over CB radio, and the time elapsed between the impact and the driver’s report. The video was also utilized to establish the location of the motorcycle along the main thoroughfare when it passed by bus 2.

The time elapsed from when the motorcycle passed by bus 2 to the time of its the collision with bus 1 was subsequently determined by subtracting the timeframes from the buses. Understanding where the motorcycle was located along the roadway when it passed bus 2, relative to the subject intersection, provided the distance that the motorcycle traveled between these two points in time. Then, using the distance and the time, the average speed of the motorcycle was calculated.

The resulting analysis indicated that the motorcycle was traveling at a speed that was twice the speed limit for the main thoroughfare. At the time that the bus 1’s driver departed the side street, the motorcycle was not within the field of view due to a curve in the roadway. The speed of the motorcycle was the precipitating factor to the occurrence of the collision, while there was nothing improper with the manner in which bus 1’s driver entered the intersection.

Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

Categories: Collision Reconstruction | Robert T. Lynch, P.E.

Tags: Dashcam | Intersection | Motorcycle | School Bus | Video Analysis