Preliminary Data on Reactions to Traffic Signals
The present dataset removes any left-turning vehicles and retains only those that are first-in-line. Thus the left-turning, white pick-up in the left of this view would be removed whereas the one in the centre and the white car on the right would be included.
Some preliminary results are available from our documentation of driver’s reactions to the change of a traffic signal from red to green. This data is for the year 2018 and includes 174 observations.
The analysis involves examining the videotape of scenarios such as the one shown above. From the instant that the traffic signal turns green we document the delay before the brake lights of the stopped vehicles become extinguished. This is what is defined as the response delay. The average response delay for all 174 observations was 0.67 seconds. But the range of responses included a situation where the brake light was extinguished 4 seconds before the activation of the green signal. And there were 10 incidents where the brake lights were extinguished before the activation of the green signal. There were also numerous observations of delays well above 1 second. The greatest delay was over 3 seconds after the signal turned green. Thus even within this small dataset we can see some wide variance in the results.
We will have more to say about the relevance of this data after we have documented enough observations. In 2019 a much larger number of observations were made and these still need to be added to our spreadsheets.
In response to various client assignments a variety of other response data has been collected in the past. In some instances involving intersection collisions a test vehicle was purposely driven forward from a side road and then stopped prior to entering the intersection. Video cameras documented the delay before approaching drivers on the main road applied their brakes.
In other instances we have documented the approach of vehicles to a traffic signal just as the signal changed from green to amber. The decision to pass through the intersection without stopping or braking to a stop was documented via videotape.
These are examples of the testing that may be discussed in the future in combination with the data that is being discussed here. There are always persons who express their opinions on what drivers should or should not do in collision scenarios. Unfortunately much of this opinion is expressed without an understanding of human behaviour, specifically in the roadway environment. Hopefully, a discussion of observations that we made in the field will anchor some beliefs to objective fact.
Do You React To A Traffic Signal Like You Do To An Impending Impact?
Do you respond to an impending collision in the same way as you respond to a traffic signal?
That question is being examined through research by Gorski Consulting. In the past fews years vehicles stopped at traffic signals have been videotaped with a dash camera in the short instance when the traffic signal turns from red to green. The observed delay is used to explore how drivers might react to similar stimuli in the short seconds before a traffic emergency.
Researchers have found it difficult to explore the reactions of drivers to emergency situations because, in order to do so, the driver must be placed in a realistic emergency situation and that could be dangerous. Recent advances with advanced simulators have made environments that appear very real and thus better data on perception-response delays are gathered. Unfortunately such simulators are extremely expensive and rare and used by only a handful of research facilities.
The Gorski Consulting research is simple and extremely cost effective. An inexpensive dash camera is used to create the video and these segments are inserted into a low-cost video-editting program. This allows a frame-by-frame study of the instant that a signal changes and the time when a vehicle’s brake lights extinguish.
This data will also be used to examine the reaction times of drivers at specific intersections to determine if the layout of the intersection makes a meaningful difference in response delays. Other factors such as the influence of other drivers will also be examined.
Preliminary results demonstrate the complexity of some responses. While we would believe that the response to a traffic signal should be relatively simple, some subtle nuances become revealed through detailed study. It is interesting how drivers will release a brake pedal slightly so that the vehicle begins to crawl forward while the brake light remains illuminated.
Also very short response delays have been observed. While delays in the range of 0.6 to 0.8 seconds could be expected, many delays are below 0.5 seconds. Presently these very short delays seem puzzling as drivers should not be capable of reacting in such short times to an emitted stimulus. Driver pre-processing of their environment and “guessing” that a signal may soon change could be an explanation for these results.
We are also observing very long delays suggesting that these drivers are not attentive to the traffic signal. This may be relevant to the issue of driver distraction.
This work is also being conducted to explore the rather simple conclusions drawn by many in the collision reconstruction community who testify in court about what a driver should have done to avoid a collision. The behaviour of humans in a complex environment cannot be narrowed to these simple conclusions as many factors affect the relationship.
Unexplained Frontal Crush to OPP SUV in Unidentified Collision
The location and severity of crush on this OPP SUV that was reported to be stopped and unoccupied is unusual as the occupants of the striking vehicle were reportedly uninjured.
Unusual things happen, but explanations would help. How does an unoccupied OPP SUV sustain major frontal damage with no injury to the occupants of the opposing vehicle?
Firstly, the front ends of OPP SUVs are very stiff. Something like a Ford Explorer that may be four-wheel-drive is difficult to crush when encountering a typical passenger car. But we add that pusher bar to the SUV’s front end and that should increase its stiffness. So we look at the photo above (which was uploaded by the OPP on their Twitter account) and we should ask: “What happened to the other vehicle?” The OPP provided no explanation about how this collision occurred.
Let us consider the most typical scenario. The OPP SUV is stopped along the roadside of Bruce Road 23 which runs north-south close to the shore of Lake Huron. At this time of year the snowfall should be considerable and we might often see this highway closed due to poor weather conditions. Normally OPP vehicles should be stopped on the right side of the road but if there is major snowfall and large snow banks the roadway could be narrowed. So the stopped position could be further onto the roadway than usual. Assuming a typical situation where snowfall may have accumulated on the highway surface the road could be slippery. The combined scenario of a narrowed road, a police cruiser that is stopped further onto the roadway than normal and a slippery road surface could provide some explanation for why a passing vehicle might collide with the cruiser. But we don’t know. All this is speculation. A meteorite might have fallen from the sky. But some explanation from the OPP would help.
We can see that the crush to the front of the OPP SUV is not minimal. Granted there is little or no crush at the bumper level and this is the stiffest portion of any light vehicle. And the softer upper portion at the grill and hood edge is where most of the crush is located. But still, this is not “minimal” crush. If the front end of a typical passenger car or light truck struck the OPP SUV you would typically see a difference in the magnitude of crush on the right versus the left corner. This is so because it is extremely rare that frontal impacts would occur “license-plate-to-license-plate”. There is some indication that the crush is greater at the right front corner than the left but that is still not typical of a front-end to front-end impact.
The visible damage pattern is more like what one would see if a vehicle went out of control and slid sideways into the front end of the cruiser. But if that happened you would see major crush to the side of the vehicle and this would be a life-threatening situation. So is that what happened and a miraculous saving of the opposing driver occurred? Possibly but not likely? It remains a curious situation.
A vast majority of impacts to stopped emergency vehicles is from the rear. This is particularly dangerous on high-speed expressways that may also have a higher number of large and heavy vehicles. Even police are sometimes not fully aware of the dangers they are in whenever they come to a traffic stop. Some things can be done to improve the chance of survival by using an emergency vehicle as a “blocking truck” until further assistance arrives to provide formal protection. But in the end it is a dangerous situation.
There is a legitimate concern why a “Move Over” law was placed in Ontario’s law books. Given the dangers that emergency personnel face, something had to be done even when, in some instances, drivers approaching stopped emergency vehicles are of minimal fault for some collisions. It is important to understand that the lives of emergency personnel are at stake. Emergency personnel who deserve to come home at night.
Ultimately, what is truly necessary is a detailed and independent study of collisions with stopped emergency vehicles. A study that is unbiased and willing to suggest large changes in how and where such stops are conducted. On major expressways some form of formal stopping location may need to be developed on all expressways. But that would only improve on a small number of incidents. The solution would not be simple and it may require a number of small solutions.
The future may be bright when vehicles begin to communicate with themselves and the roadway itself. It may be possible to control all traffic around the vicinity of stopped emergency vehicles and that would be a huge improvement. But such communications are still a long way in the future.
In the meantime drivers need to consider that the lives of emergency personnel are valuable to us all. While imperfect the Move Over Law is correct. When you see, or suspect, that emergency vehicles may be stopped on the road, slow down and attempt to provide lateral distance between your vehicle and those stopped vehicles. And be alert to the possibility that pedestrians traffic may be present. But do not panic. Sudden hard braking or lane changes without thinking will make matters worse. Drive predictably so that other drivers understand your intentions.
Transport Truck Collisions In Winter: A Demonstration of Expressway Safety Problems
This example of severe structural intrusion was provided by the OPP from an unidentified collision on Highway 401 near Tilbury, Ontario on February 27, 2020. Unfortunately how it occurred was never revealed.
Poor weather, large numbers of heavy trucks and a lack of safety education are a toxic mix on Ontario’s expressways. This has been made apparent again when a winter storm passed through southern Ontario in the past couple of days. Police posted warnings before the storm and they posted warnings during the storm: “When you see snow go slow”, and similar sage sayings.But that did not stop the sharp increase in collisions that occurred. And these increases occur every time a winter storm passes through. By now it would seem that the broken record has been playing the same tune too long and it’s time to change the record.
Rather than calling the same tune is it not wise to admit that something keeps reoccurring and that an understanding is needed why we cannot stop massive numbers of collisions in winter storms? Every year well over 200,000 collisions are documented and sent to Ontario’s Ministry of Transportation. Various sensors are imbedded in roadways that monitor traffic. Traffic cameras are increasing in exponential numbers. All this information seems to be deposited into a black hole with no chance of coming back out to the public that needs it.
The safety information provided on the Gorski Consulting website is one of the few independent sources that is not involved in this all-encompassing vortex. While the views expressed may not be shared by all, an attempt is made to provide objective facts and remain unbiased.
What is observed is that winter storms and heavy truck transportation are a particular problem on Ontario’s expressways. Even on pleasant days with dry road surfaces and clear visibility the drivers of heavy trucks are at a disadvantage due to their lessened ability to brake, difficulties in seeing everything around them, and the simple fact that the very large masses they haul can potentially have devastating consequences to them and those drivers around them.
Highway 401 is perhaps the best example of these problems as it is the longest expressway in Ontario, stretching well over 800 kilometres between Windsor and the Quebec border. Very large percentages of trucks use this highway. And high percentages of these trucks are on long-haul missions that take them to all parts of North America.
When truck drivers travel long distances in winter, without many stops, they can approach a weather system and pass through it, experiencing various environmental changes that are important to their safety. It would not be unusual for example, for a westbound truck driver to enter Highway 401 at the Quebec border and experience sunny and dry conditions. But storms that approach from the west can sometimes travel as fast as the trucks themselves. Thus the closing speed between a westbound truck and a storm can be at 200 km/h. This rapid approach means that highway conditions can change rapidly. Our westbound trucker at the Quebec border could experience a severe winter storm by the time he reaches Kingston, which is just over 200 kilometres away, even though the storm might have been in Toronto when the trucker entered Ontario. And that storm might lose most of its effect by the time the trucker reaches London which is another 200 kilometres to the west of Toronto. While it is easy to say that one must drive for the road conditions, when those conditions change rapidly, not all drivers will detect deteriorating conditions at ideal times.
Due to the very large numbers of units involved it only takes a few drivers who misinterpret the conditions for the creation of a potential safety nightmare. Traffic volumes are below 20,000 units per day near the Quebec border, they increase to over 400,000 through the centre of Toronto and they fall back to below 20,000 again in some parts approaching Windsor. A misinterpretation by just 1 in 200,000 drivers could result in a major catastrophe. Yet how many of us, in whatever task we may select, have failed to perceive something or failed to perform a task properly that we have done 200,000 times previously with success? In fact a success rate of 199,999 times in 200,000, would seem to be very good. Yet in the deadly environment of traffic conflicts many of us perceive this as horribly inadequate.
Winter storms change road surface conditions and we refuse to admit that those changes are sometimes difficult to detect. In the early onset of a storm the small quantities of snow that fall on a road surface can change the tire force dramatically. In one instance temperatures and minimal wind can create a wet surface with a co-efficient of friction in the range of 0.5g. Alternatively, a slightly colder temperature with higher winds can change that surface to an icy mix that is not consistent along the length of the highway. Icing becomes sporatical depending on local characteristics where elevation changes and exposure to wind drop the co-efficient of friction below 0.2g. In comparison the same surface in dry conditions might provide a value in the range of 0.6g for trucks. Is that important?
With maximum braking on a dry surface with 0.6g, a truck with a fully functioning braking system will stop from a speed of 100 km/h in just slightly less than 80 metres. Under the same scenario but a co-efficient of friction of 0.5g, the same truck would need slightly less than 90 metres to come to as stop. But on an icy surface that has a co-efficient of friction of 0.2g, a distance of about 200 metres is needed to come to a stop. This difference is dramatic.
What we fail to ask is whether a truck driver can easily detect the difference between wet and icy road surfaces. In both instances there could be snowfall or snow accumulated on roadsides. But in the vicinity of where the truck’s wheels travel, within a lane, the road surface could be bare of such snow. What may remain is a dark asphalt surface that could either be wet or icy. Both conditions could cause reflections of light into the driver’s eyes where that light needs to be processed and an understanding needs to be made. So is that easy to do? In our view the answer is no in a significant number of instances. Enough so that misinterpretation of surface conditions is a common occurrence in winter driving.
We can combine these road surface problems with issues of poor visibility. Every driver has experienced those winter situations where snowfall or even strong winds can produce white outs. But even less intense scenarios can be problematic. Even in good weather, without additional and specific cues, drivers have difficulty detecting the speed of vehicles that are ahead of them by more than about 175 metres. Once a slow-moving vehicle is detected there no guarantee that the precise speed will be known, only that the vehicle may be moving slowly or stopped. But that encompasses a very wide range of possible speeds. A speed of 80 km/h would be considered slow for a typical expressway. But even in poor weather conditions most drivers drive faster than advisable. Under these conditions truck drivers expect other vehicles to be going at least 80 km/h but not 40, or stopped. And hazard lights are not always activated. Yet early detection of slowed traffic is more important for truck drivers than for drivers of smaller vehicles that have more efficient braking systems.
We can combine a further problem with the road surface condition and the visibility problems: The incompatibility of trucks and small cars. Many car drivers do not appreciate the limited visibility that is available to truck drivers. A truck driver that wants to make a lane change must look a long distance behind the truck trailer to evaluate whether his truck may interfere with a car that is approaching from behind often at a much higher speed. Heavy trucks can require as much as 10 seconds to make a full lane change and in that time the truck could travel close to 300 metres. A car travelling at 130 km/h travels about 36 metres every second, so in 10 seconds it could travel about 360 metres. Thus, even from a long distance back, the speeding car driver could reach the back of the truck’s trailer long before the truck has had a chance to complete its lane change. It is no wonder that some speeding car drivers think that truckers are intentionally interfering with their right to speed.
Another problem in three-lane traffic is that many long-haul truck drivers become fed-up with constantly weaving in and out of the slow (right) lane as vehicles merge from entrance ramps or slower trucks are encountered. So they will purposely drive in the middle lane where there is less interference. But when the right lane is open many car drivers will use that lane to pass a truck especially when the fast lane is crowded with traffic. A number of dangers develop from this situation. First of all car drivers do not fully see the length of the slow lane ahead when they steer into it from behind a long and wide truck. Unexpected slow vehicles, or even vehicles that have encountered an emergency might be stopped in the lane without being detected in time. Any impact involving other vehicles has a good chance of involving a nearby heavy truck simple because the length and width of the truck takes up some much of the highway.
We have all been exposed to the Move Over law which requires drivers to move away from a lane or shoulder where an emergency vehicle may be stopped. When car drivers drive into the right lane from behind a truck they may not detect emergency vehicles even with all the emergency lights being illuminated.
Why can drivers not see the high-powered emergency lights on numerous emergency vehicles parked on the side of Highway 401 and therefore move over? There is no conceivable excuse for this lack of attention. We can do better with this logic as shown in this recent example.
There is also the common problem that truck drivers have poor visibility of small cars that are located near the road tractor’s right front wheel or just in front of the road tractor’s right front corner. A number of collisions occur where the truck driver claims that he did not see any vehicles when he steers into the right lane.
Further problems exist because heavy trucks are so wide and they are buffeted by winds causing trucks to move out of a lane. Although the travel lanes of expressways are extra-wide, usually about 4.0 metres, a heavy truck that is about 2.6 metres wide must use that lane just like a small passenger car that may be only 1.5 metres in width. When large gusts of wind come small cars are often of a more aerodynamic design that prevents them from being blown from side to side. That is not the same for heavy trucks that may be hauling empty, 52-foot long, semi-trailers. Such trailers have little design to reduce their being blown out of a travel lane. The problem with this should be obvious.
And the final issue that will be mentioned in this article is the one of lane closures from road construction or emergency road operations. When lane closures occur on busy expressways the highway may become clogged up for many kilometres back from the actual lane closure. The most dangerous time is when vehicles are approaching the back of the que of stopped vehicles. Although truck drivers sit higher off the ground and therefore are able to detect stopped traffic ahead sooner, sometimes those trucks are travelling very close behind each other and visibility ahead is almost non-existent. When a truck driver brakes suddenly others behind may not react quickly enough such that the braking of the following truck becomes more severe. It does not take much thought to understand that the third or fourth or any other truck further behind may not be able to stop even when applying maximum braking. Thus a rear-end impact occurs. And that rear-end impact can make problems worse as other truck drivers further behind have little time and distance to detect that an impact is occurring because they are also too close behind the truck ahead. Some of the worse multi-vehicle pile-ups occur from this type of scenario. The installation of Automatic Emergency Braking on heavy trucks would be of great benefit in so many of these scenarios. Yet governments are slow in making this mandatory.
While adding additional lanes and concrete median barriers can help in some expressway situations, the fact is that these will not stop many collisions from happening. What is needed is a thorough and detailed study of traffic on expressways to understand what conflicts exist and this leads to the final comment in this article.
Policy-makers in Ontario have created some bazaar and dangerous situations, perhaps because they have spent too much time examining the contents of large traffic databases and not understanding that some real-life conditions are not accurately reflected in large scale data.
Strange as it may seem the purpose of creating inaccurate data is not always benign. Inaccurate data can be of benefit to those who are required to take action when a real-life problem exists, but that problem is masked by the existence of inaccurate data which demonstrates that no action is required. Hiding traffic data or making that data inaccurate can be a benefit to those who may be held accountable should good and accurate data reveal their inappropriate actions.
Traffic conflicts can be represented by a pyramid where the small number of fatal collisions are at the very peak. Below are a larger number of injury-producing collisions that are still very small in number compared to the overall number of conflicts. The much large number of collisions are those reportable ones where injuries do not occur. But many of these reportable collisions are only reported to a Collision Reporting Centre and the report contents are based on the verbal or written information provided by the involved drivers. This makes for poor or no information being gathered about the causes of many of those large numbers of reported collisions.
At the bottom of the pyramid are those vast numbers of incidents and collisions that never make it to the Ontario Provincial statistics. These are collisions of less monetary loss that are often single vehicle incidents where there is only one driver and no one else involved. Research by Gorski Consulting suggests that these unreported incidents could be well over 80 per cent of all collisions or incidents, or that less than 20 per cent of the full number of collisions or incidents are ever reported. Many argue that these incidents are meaningless as their results are of little consequence. Yet the fact that the incident occurred could illuminate a safety issue that has not yet reached the level of causing a more serious incident and so these non-reported incidents could be the canaries in the coal mine.
The reality is that Provincial and Federal data files of collisions are often incapable of detecting certain safety issues because they do not contain the much larger number of incidents of a minor nature that occur in official blindness. When analysts examine a reported collision they do not have information about 8 or 9 others that have also occurred but have not been officially documented. Even though very large numbers of collisions are reported every year, they are all taken from a small slice of the overall pie, and each year the same slice is sampled from the same part of the pie. What exists in the rest of the pie unknown.
Let us use this simple analogy. A restaurant owner wishes to serve a pie to his valued customers and always slices a piece off for his personal testing and evaluation. Meanwhile the baker has mistakenly placed pepper in a specific area of the pie which is never sampled by the owner. A random slice of the pie is sent off to the customers who, tasting pepper, are outraged and never return to the restaurant. In the traffic case the owner (Provincial government) does not care whether the customer comes back because the government has a monopoly on dishing out pies to all its citizens. So you either eat the Government’s pies or you do not eat at all.
But we should have an option to change this. The public should have the right to sample the whole pie and not just at the same spot but where ever the public choses. We can take action to remove the “pepper” in our collision statistics. That should be our democratic right.
Failures at Hwy 403 Median Cross-over Collision Near Brantford
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.
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