Officially, the cause of a loss-of-control, median cross-over collision on Highway 403 near Brantford yesterday is claimed to be unknown. But certain facts point to failures and possible causes. Without official presence during the investigation it is difficult to discuss these causes when the official investigators have not revealed them.

The OPP reported that yesterday, shortly before 1800 hours, a eastbound car was travelling east of Wayne Gretzky Parkway on the east side of Brantford, Ontario. For unknown reasons the vehicle entered the centre median and became airborne, colliding with a westbound transport truck. The car was ripped in half and the driver was ejected. The driver was  taken to hospital with life-threatening injuries. A video description of the preliminary findings were presented by the OPP on their Twitter account.

The photo below is a frame taken from the OPP video showing the final rest position of the car that was “ripped in half”. It is lying against a guardrail on the north side of the highway. Certainly the front portion of the vehicle is missing but the roof is generally intact. It can be noted that there is a substantial amount of snow visible in foreground. The visible area containing the snow is located in the westbound right lane.

In the next frame below we are looking westward in the westbound lanes of Highway 403. The larger orange circle is highlighting some damage to the guardrail and this is likely where the car passed through it just before impacting the transport truck. Note the yellow warning sign at the left edge of the view: This sign will be shown in other Gooplemaps views to establish the precise location of the collision. In the background is a smaller circle which highlights the location of the stopped position of the transport truck. To the right is a view of a light-coloured pick-up truck that sustained damage from the collision debris but was otherwise not involved in the collision. The location of the detached front portion of the car is not very visible in this view but it is located near another yellow warning sign (between the transport truck and the pick-up truck) on the north (right) side of this view.

The next frame takes us further west along the westbound lanes of the highway. We might just be able to detect the front end of the light-coloured pick-up truck at the extreme right edge of the view. The larger orange circle highlights the location of the front portion of the car. The smaller circle highlights the location of the transport truck.

It can be noted in the two previous frames is that the westbound lanes of the highway are snow-covered. But there is no video showing the conditions in the eastbound lanes where the car went out of control.

So what is important about these findings? A vehicle crossing through the median of a major expressway is not a desirable occurrence. This fact is well-publicized in the controversy that exists with the lack of a concrete median barrier along Highway 401 between London and Tilbury. It was also recognized in the 1980s and 1990s before a concrete barrier was built along Highway 401 between London and Woodstock. So there has been ample warning about the dangers of median cross-over collisions for many decades.

What is perplexing about the OPP video discussing the collision is that the cause of the median crossover was not mentioned. Not only was it not mentioned but there was no video presented of the conditions of the eastbound lanes of the highway where the car originally went out of control. The precise location of this collision was also not mentioned so it would be difficult for anyone wanting to consider a possible cause to do so.

In order to identify the collision location we used the location of the yellow warning sign on the median side of the westbound lanes that was shown in the police video and also shown in one of the frames above. On May 15, 2019 Gorski Consulting conducted testing along the westbound lanes of Hwy 403 and part of that testing covered the area between Garden Ave and the Wayne Gretzky Parkway where this collision occurred. The testing included multiple video cameras that were attached to the test vehicle. A video project was created combining those video views. Below is a frame taken from that May 15th, 2019 video project showing five camera views. In the largest camera view at the bottom left of the frame one can detect the yellow warning  sign in the median and this is the same warning sign that was shown in the police video. So this is the way we determined the precise location of the collision.

The location shown in the above frame is just before the test vehicle reaches a railway bridge. As this view is looking westward the bridge also exists in the eastbound lanes of the highway.

The figure below is a Googlemaps view of the collision site where we have inserted several captions to highlight some important facts. North is at the top of the figure. An orange line shows the eastbound path of the car as it passed over the railway bridge and over the two junctions to the bridge on the roadway surface. The orange circle points to the fact that the guardrail that is present along the bridge terminates about 50 metres east of the east junction of the bridge. The orange arc generally demonstrates that the car crossed the median east of the location where the guardrail came to an end.

The Googlemaps view below shows a view looking eastward along the eastbound lanes of Hwy 403 at the precise location where a black car is about to crossover the east junction of the railway bridge. In the background one can see the guardrail on the median side of the lanes just past the concrete abutment of the bridge. Crossing over a bridge junction like this is known to cause a disturbance in a vehicle’s motion.

In the following figure we can see the black car as it continues to travel past the railway bridge and it comes to the end of the guardrail. Remember the termination point of this guardrail is only 50 metres past the east junction the pavement of the highway.

At a typical, average, highway speed of 110 km/h, a vehicle travels about 30.5 metres every second. So the 50 metre distance between the bridge junction in the pavement and the end of the guardrail would be traversed in about 1.6 seconds.

As shown in the frame below, once the black car passes the end of the guardrail there is nothing to prevent its potential loss-of-control travel through the median until it strikes the backside of the guardrail at the westbound lanes portion of the median.

The OPP are the only entity allowed onto a collision site such as this and the highway is closed preventing anyone of coming out to examine the evidence. So it is highly important that the OPP document the evidence that could identify the cause of this collision. Not only to settle matters of criminal and civil liability but it is crucial to the determination of safety-related causes that need to be identified and corrected to protect all of the travelling public.

A crucial part of a professional investigation and reconstruction is to document the highway surface conditions. Although one can see from the OPP video that the westbound lanes were snow-covered nothing was mentioned about the eastbound lanes where the car went out of control and there was no video showing those eastbound lanes. Granted this is early in the investigation but still, why was no mention made?

Police, like any professional analysts must accept that road surface conditions can be a cause of collisions. But rain, snow and ice are not the only factors that must be considered. The actual, physical character of the highway must be considered. Thus an investigator must know something about the accepted curve radii for a given highway design, the acceptable cross-slope of the surface of a travel lane, what roadside objects can pose an unacceptable danger, and whether any road surface bumps, ruptures, depressions may become an unacceptable danger.

Specifically with road surface issues, investigators must have an understanding that the threat of any road surface disturbances change, not only with vehicle speeds and motions but also with environmental conditions. Thus a certain roadway depression for example, may be traversed in relative safety when the vehicle is travelling at constant speed, in a straight line and on dry pavement.

However there are many occasions when drivers must accelerate or brake or steer to change lanes. Whenever these actions are performed there is an increase in the demand for tire force. And when a road surface is dry there is plenty of tire force to complete these actions in safety. But an investigator must also consider that a driver could make an acceleration, or a braking action, or might conduct a steering action while travelling over the surface depression and the road surface may not be dry. What happens when the highway surface becomes wet, or snow-covered or icy. In each of these conditions the level of available tire force is reduced.

In the Gorski Consulting testing the extent of vehicle motion was monitored as a test vehicle travelled westward along Hwy 403. In the vicinity of the railway bridge the vehicle’s motion was disturbed when it travelled over the junctions of the bridge on the highway surface. The extent of this disturbance can be seen in the chart shown below which covers a travel time of about 30 seconds or a travel distance of about 800 metres. The two large disturbances just before the middle of the data were caused when crossing the two junctions of the railway bridge.

The above chart shows how the effects of driving over a bridge junction are not always the same. It shows that the effect of the first junction was much more severe than driving over the second junction. So it does not help to make brought generalizations about such effects but one must actually examine each site where such junctions exist to determine if an unacceptable condition exists.

We do not know the status of the junctions of the railway bridge in the eastbound lanes of Hwy 403 because no testing was conducted in those lanes. But examining the results from travelling over the westbound lanes demonstrates the need to consider the junctions as a cause for the car’s loss-of-control. This is particularly so when the vehicle enters the median shortly after crossing those junctions.

In general, in most investigations of serious collisions there is essentially no analysis conducted to evaluate certain road conditions such as road surface problems as causes of collisions or as factors that increase the severity of collision consequences. This is not helpful. More has to be done to ensure that investigations are sufficiently independent and unbiased so that they do not hide roadway problems that may be a danger to all users of our roadways.