Rider Error or Evasive Maneuver?


Curt M. Beloy, P.E. ::::

Case Synopsis: A head-on collision occurred between a motorcyclist and a minivan.  DJS Associates collected data at the site (including tire marks, scrapes and roadway geometry) and from the vehicles, as well as performed a reconstruction of the collision based on the physical evidence and available data.  The physical evidence defined that the motorcyclist had crossed the centerline and was within the oncoming travel lane at the time of the collision.

Analysis: According to the motorcyclist’s testimony, he was entering a curve in the road when he observed the minivan encroaching in his travel lane.  He further indicated that he attempted to avoid the minivan by steering into the oncoming lane, at which time the minivan swerved back into its lane where the collision occurred. 

The reconstruction analysis, based on the laws of physics, not only established the location of the collision on the roadway, but also the speeds of the vehicles just prior to the collision.  A three-dimensional model of the roadway and roadside was created utilizing high-definition surveying [HDS] measurements gathered at the site.  In the three-dimensional roadway model, the views of each vehicle operator were evaluated in the moments leading up to the collision based on the reconstruction analysis.  The data established that at the moment the motorcyclist perceived a hazard and reacted by applying the brakes, the minivan was not within view due to a sight obstruction on the inside of the curve.

Conclusion: The engineering analysis indicated that the physical evidence was consistent with the motorcyclist traveling too fast for the curve in the road, failed to remain in his travel lane, and crossed the centerline of the roadway into the oncoming lane resulting in the collision.

Categories: Case Studies


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