Case Studies
According to the motor vehicle collision report, a collision occurred on a county road on an unlit driveway to a private property at approximately 6:00 AM in November (prior to sunrise). According to the provided information, an initially westbound tractor-trailer was attempting to reverse into the driveway on the south side of the road, with the trailer entirely across the eastbound lane of the county road. An eastbound passenger vehicle (a Ford sedan) struck the trailer. After this initial impact, another eastbound passenger vehicle (a Dodge SUV), also struck the trailer.
Our client, acting for one of the plaintiff drivers of the passenger vehicles, requested we reconstruct the collision and determine whether his client had any opportunity to avoid the collision with the trailer.
Through testing at the scene under similar conditions, our team found that the lighting at the incident scene was extremely poor. At the time of the collision, the sun had not yet risen, and the area was still completely dark with no artificial lighting provided. Lighting measurements taken at the scene found that the ambient lighting was less than one lux in the area of the incident collision. Further testing was conducted at the scene by closing the road, positioning an exemplar tractor-trailer across the lanes of traffic as it would have appeared to the plaintiffs at the time of the impact, then approaching in an exemplar vehicle at a similar time of night. We found that an aware and stationary observer could only begin to detect the reflective striping of the box trailer when the observer was positioned approximately 110 meters from the area of impact. After accounting for expectancy and the driving task, it is expected that a typical driver in the plaintiffs’ position would only have been able to begin reacting to the stopped trailer across their lane when they were positioned approximately 37 meters from the area of impact. The collision analysis considered various factors, including human factors such as cognitive load and situational awareness, to better understand the driver's behavior leading up to the incident collision.
At the plaintiff’s approach speed (approximately 95 km/h, based on data from the vehicle’s restraints control module), the collision was unavoidable and inevitable. Our analysis found that the perception response time (or “reaction time”) of a typical driver in the plaintiff’s position did not allow for adequate braking to avoid the collision. Further, even at the posted speed limit of 80 km/h, a typical driver in the plaintiff’s position would not have been able to avoid the collision. This conclusion was supported by the fact that shortly after this first impact, a second vehicle traveling in the same direction as the first also collided with the stationary tractor-trailer.
Several similar collisions had been investigated prior to this example case, and, unfortunately, similar cases continue to occur. Despite this, there are currently no regulations in Ontario to prohibit heavy vehicles from turning into unlit driveways on dark and unlit roads. The hazard caused by these large vehicles occupying both lanes of traffic for significant portions of time causes unnecessary and preventable injury and damage. Caution should be taken by property owners to ensure adequate lighting is provided in the surrounding area when trucks are expected to be turning into or out of driveways on unlit roads under dark conditions.
Sam Kodsi, B.Eng., P.Eng.
Consulting Forensic Engineer
Accident Reconstruction
+1 647 558 3865
[email protected]
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J.S. Held’s accident reconstruction experts deliver specialized expertise in forensic investigations, evidence collection and preservation, and scientific diagrams and animations. Our team of consultants, engineers, and PhD scientists is retained by first-party and third-party clients to provide expert witness and litigation support, from discovery to decision.
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