Speed Bump Aggressiveness As Part of Collision Cause Analysis
Motor vehicle collisions are caused by many factors including the characteristics of a road surface. Vehicle reactions to speed bumps can lead to understanding how uneven road surfaces can cause collisions. The following is an example.
At approximately 0330 hours on Sunday, October 26, 2019, a Mercedes vehicle was northbound on Wilson Ave, just west of downtown in London, Ontario. Upon approaching the T-intersection with Blackfriars Street the vehicle went out of control. It knocked down two utility poles, then struck a commercial building on the west side of Wilson, it was then deflected and impacted a residential house on the opposite side of the T-intersection. News media reporting on the collision described the site as a “war zone”. A woman sleeping in the struck residence was lucky to escape injury as a neighbour reported that “Her head was a couple of feet from where the car stopped”.
The Google Maps view below shows the full length of Wilson Ave between Dundas Street to the south and Blackfriars Street to the north. The area of impact is located at the very top edge of the view denoted by the caption “Society Cafe”.
Google Maps view of Wilson Ave just west of downtown London, Ontario. The impact occurred at the top of this view at the commercial building labelled “Society Cafe”.
Gorski Consulting attended the site on October 28th and the following images provide some detail to the amount of carnage that occurred about 36 hours earlier.
View looking north on Wilson Ave showing the damage caused to the east wall of the commercial building (“Society Cafe”) from the impact by the Mercedes. In the background is the residential house which was also struck.
View looking north toward the struck residence on the far side of the T-intersection at Wilson Ave and Blackfriars Street.
View looking north on Wilson Ave showing one of the utility poles (now replaced) that had been knocked down by the Mercedes before it struck the commercial building.
Looking from a distance south of the impacts we were able to detect a loss-of-control tire mark that demonstrated that the Mercedes rotated counter-clockwise on the road before travelling onto the west roadside. Two photos below contain orange arrows that identify the location of the “yaw” tire mark.
Two orange arrows depict the location of a curving, “yaw”, tire mark that demonstrates the path of the Mercedes.
Two orange arrows depict the location of the tire mark caused by the Mercedes before it exited the west side of Wilson Ave.
Backing up further to the south we observed the location of a speed bump on Wilson Ave. Using Googlemaps we estimated that the bump was located about 154 metres south of the intersection with Blackfriars, or about 126 metres south of the first struck utility pole.
View looking north along Wilson Ave where a speed bump can be seen along with a yellow warning sign identifying its location.
View of the speed bump located on Wilson Ave approximately 156 metres south of the T-intersection with Blackfriars Street.
When we walked further to the south the photo below shows that the yellow warning sign can still be seen however a truck and trailer was parked on the east side of Wilson and the following photo, taken from further to the south, shows that the warning sign is no longer visible as it is blocked from view by the parked vehicle.
View looking north along Wilson Ave demonstrating how a parked vehicle could block the view of northbound drivers of the presence of the speed bump sign.
View looking north along Wilson Ave showing how the warning sign is blocked by a vehicle and its trailer.
Further examinations revealed that there were four speed bumps located along the approximate 725 metre length of Wilson Ave from Dundas Street through to Blackfriars Street. It could not be expected that a northbound driver could be oblivious to the presence of all these speed bumps even though some of the warning signs might have been blocked from view. However there was no information made available whether the collision-involved Mercedes travelled the full length of Wilson or if perhaps the vehicle turned onto Wilson from one of the crossroads. Thus it is possible that the driver might have experienced a couple, or even just one of the speed bumps before experiencing the loss of control.
There is no question that the collision-involved Mercedes was travelling very quickly, and likely at highway speed along a narrow residential street posted with a maximum speed limit of just 50 km/h. So why did this occur? If the driver was familiar with the roadway then he/she should have been aware of the presence of the speed bumps. And one would expect that any driver would find it uncomfortable to travel over a speed bump at highway speed. Any driver can appreciate that a speed bump is designed to discourage high speeds and that driving over a speed bump at high speed should have a major effect on the motion of the vehicle and its control. But how much objective knowledge is there other than a subjective opinion or conclusion? And what if a vehicle travelled over a road surface feature that was similar to a speed bump but not designed to be there? For example a depression in a road surface might cause a similar disruption to the motion of a vehicle. But what objective data exists about the effects that this might have on the control of a vehicle and the possibility that it might cause a collision?
A few years ago, as a result of a civil suit, Zygmunt Gorski was part of a team of experts that came together with an opposing team of experts whereby a decision was to be hammered out whether a road surface “undulation” or depression had led to the loss-of-control of a vehicle on a rural highway. The collision led to massive injuries to two vehicle occupants. Hundreds of thousands of dollars were paid out in consulting fees just from the experts, not including the lawyers fees. Several meetings of the experts were arranged by the court and a mandatory report of our findings was to be prepared. In the end essentially nothing useful was developed as even the most basic terms and beliefs could not be agreed upon by the experts. None of the experts could present basic data on the effects that a road surface bump, depression or undulation might have on a vehicle. Essentially there was no such data. In the realm of civil suits such data is often hidden by both sides for strategic reasons. And the costs of conducting laser scans or employing road surface profilers prohibit the development of useful data except in a few high-cost cases. A simple instrument, following a simple procedure, and low cost, could be helpful, not only in court proceedings but in educating the public about how the characteristics of road surfaces can effect vehicle motions.
These are some of the reasons why attempts have been made by Gorski Consulting to develop some objective data to answer this question of the relationship between road surface conditions and collision causation. As mentioned many times in previous articles, a Road Data file exists on the Gorski Consulting website which contains a list of all the sites throughout southern Ontario where testing has been performed. Several articles have been posted on the Gorski Consulting website describing the testing procedures and the meaning of the results. Some testing has involved very short road segments where the test vehicle has crossed over bridge junctions, railway tracks, incomplete road repairs and speed bumps.
With specific relevance to the Wilson Ave collision, in 2018 Gorski Consulting conducted some testing on a set of five speed bumps located on Edmonton Street in London, Ontario. These bumps were selected because of the subjective sensation that they caused overly large reactions of vehicles passing over them. Views of the Edmonton site are shown below.
The orange circles in this image identify the locations of 5 speed bumps on Edmonton St between Wavell and Dundas Streets in London, Ontario.
View looking north on Edmonton Street toward the first speed bump located in the background.
View looking north along Edmonton Street toward the first speed bump.
In the 2018 testing a 2007 Buick Allure was driven at approximately 30 km/h in both north and south directions on Edmonton Street and the motion of the vehicle was documented as noted in the table below.
The data from the above table is shown in the chart below.
In an article (“New Test Data of Speed Bump Aggressiveness”) discussing the testing, published on July 2, 2018, a table erroneously reported the Longitudinal Rotation during the northbound crossing of the 2nd Speed Bump as 0.2669 radians per second. This error has now been corrected in the above table and chart to correctly read 0.1758 radians per second.
On May 18, 2021 we conducted further testing at the Edmonton site using a similar procedure. However we used a 2012 GMC 18-Passenger School Bus in the new testing. The results from this new testing are shown in the table and chart below.
Further testing was also conducted on May 11, 2021 using the same GMC school bus but along a different route in London, Ontario. The route followed Cranbrook Road, Vicount Road and Farnham Road. The route is shown in the Googlemaps view below.
A table and chart from the May 11, 2021 testing are shown below.
Further testing was conducted along Wilson Street on May 25, 2021. The same 18-passenger school bus was driven northbound and southbound over the four speed bumps at the same speed (30 km/h) as the other two sites. The results from this testing are shown below, with tabular form, and also as a chart.
Discussion
The results from the four testing sessions can be summarized for the average Longitudinal and Lateral motion:
2018 Edmonton: Longitudinal = 0.1660, Lateral = 0.0777
2021 Edmonton: Longitudinal = 0.1654, Lateral = 0.0933
2021 Cranbrook: Longitudinal = 0.1495, Lateral = 0.0474
2021 Wilson: Longitudinal = 0.1922, Lateral = 0.1018
What stands out in these values in that the speed bumps on the Edmonton Street site produced higher levels of motion than the Cranbrook Road route. The school bus driven on the Edmonton site in May of 2021 experienced a higher level of lateral rotation than the Buick passenger car used in the 2018 testing. So we would expect that finding to continue on the Cranbrook site which was also driven by the same school bus. Yet we see a greatly reduced level of lateral motion of the school bus (0.0474) on the Cranbrook site.
Next, we see an even larger effect on the school bus at the Wilson Ave site. Both the longitudinal and lateral motions of the school bus were higher than at the Edmonton and Cranbrook sites. This effect has to be related to the difference in the speed bumps and not due to the characteristics of the school bus. Or, possibly, that the characteristics of the school bus, such as the track width and wheelbase, interacted with the differences in the speed bumps to cause the end result.
Since the Mercedes was northbound when it passed over the 4th Speed Bump on Wilson Ave, we can take a closer look at the individual samples over the 2-second interval from the testing that was conducted on May 25, 2021. This data is shown below.
What should be obvious in the above graph is that the peak longitudinal rotation and the peak lateral rotation occurred a the same time. And both of these peaks are quite high (over 0.5000 radians per second). Not only was the front end of the bus lifted but the bus was also rotated sideways at the same time, in a very short time frame of about a 1/3 of second (approximately 8 samples). Very short vibrations with high peaks can be irrelevant however this time of about 350 milliseconds is long enough to be of relevance.
This is an example of a single result and if the bus was driven over the same speed bump several times we might get quite different results. However this fact is educational in that it demonstrates that vehicles reactions to the same roadway features may be different from one instance to the next. When an investigator conducts one or two tests it is likely that the full range of possibilities may not be demonstrated in the data. Closer consideration is needed before drawing a conclusion whether a roadway feature may have contributed to a loss-of-control collision.
By performing these tests we are developing more and more data that is becoming useful in understanding what is important in evaluating the road conditions that effect a vehicle’s motion. It can be noted what we have not conducted any measurements of any of the speed bumps in this testing. Nor have be conducted any measurements of any of the other roadways on which our testing has been conducted and reported in the Road Data file contained in the Gorski Consulting website. This testing simply involves an examination of the reaction of a motor vehicle to the road characteristics.
The usefulness of the procedures discussed here is in their simplicity and cost effectiveness. The performance of any road can be evaluated by anyone who possesses a smartphone such as the Apple iPhone. No specialized equipment is needed. A couple of video cameras are needed but these can be purchased at very low costs. Through training and experience anyone can examine the results of their testing and be able to determine, in a objective manner, whether the characteristics of a road may have contributed to a motor vehicle collision.
Cause of Deaths in Recent Collision Fires Not Revealed
Two recent fatal collisions demonstrate the lack of attention being paid to the cause of death in a vehicle collision.
News media reported on May 4, 2021 that a two-vehicle collision occurred near Milverton, Ontario which resulted the death of an 84-year-old male occupant. No mention was made of a fire. Another news agency then provided on-site video footage that clearly showed a large fire had consumed a vehicle.
In a second incident, on Saturday, May 8, 2021, Peel Regional Police reported that a driver of a single vehicle was deceased as a result of a collision on Burnhamthorpe Rd in Mississauga Ontario. Mention was made of a vehicle fire but no explanation was given with respect to its relevance to the deceased.
In both instances a pattern of non-disclosure emerges that has gone on for many years and this is consistent with other reports of deaths in collisions. While police and news media are quick to report causal factors such as alcohol impairment, driver distraction, vehicle issues, etc., rarely is it reported that a post-collision vehicle fire may have led to a death. The cause of a death needs to be known whether it is caused by inappropriate actions of a driver, vehicular issues or roadway issues. When police make decisions about what they will reveal, that hide problems that could endanger the public, they contribute to the future death and injury of future occupants who are unaware of those dangers. This bias must be corrected.
Better Collision Information Combats Speculation – A Simple Recipe
In reporting of collisions to the general public withholding of evidence inevitably leads to speculation. The consequences of such speculation are not always benign nor publicly recognized.
A case in point is a reported collision on Highway 401 near Renforth Drive in Mississauga, Ontario, on April 26, 2021 as reported on the OPP Twitter account. The OPP notification did not provide any information about how the collision occurred, however three photos were provided and are shown below.
The OPP need be commended for their transparency which is better than other police forces in Ontario. When major collisions occur on expressways such as Highway 401 they frequently post photos of the vehicles and site on social media. But this is not necessarily because of their ethical sense of duty. It is more likely because they are aware that drivers passing by collision sites take photos. This photo-taking is a distraction and could place emergency personnel and others in danger. By providing photos the OPP discourage the need for the public to reveal something valuable that they may feel they are revealing. Yet even these few photos provide little explanation for why collisions occur and, more importantly, how and why a serious injury or death occurred.
In the first photo above we can see that a heavy vehicle has struck a portable concrete barrier that appears to be in a construction zone. The truck can be seen lying on its left side in the background. In the foreground, at the bottom, we have inserted an orange oval to highlight the presence of a black tire mark near the top of the concrete barrier. Undoubtedly this tire mark was caused by one of the tires of the heavy truck. Vehicles that strike such barriers are supposed to slide against the wall and come to a stop over a long distance and in an upright position. But that is not what has happened.
In the second photo we see a considerable transfer or rubber material onto most of the left side of a white passenger car. The characteristics and height of the marking indicates that this was caused by one or more tires of the heavy truck. The characteristic smudging of the rubber transfer indicates that the tires of the truck were rotating at the time of contact. The quantity of this transfer indicates that the two vehicles were in contact for an extended time.
In the third photo we see the underside of the truck. We have inserted an orange oval to illustrate the buckling of the centre link of the truck’s steering system and the presence of a white transfer which is likely from contact with the concrete of the barrier. So it appears as if the underside of the truck has made contact with the concrete barrier.
If we return to the first photo and look at the surroundings, we can see that there is westbound traffic to the left and right of the barrier. So this does not appear to be an incident where the truck was steering to the right in an attempt to exit the highway and therefore drove into the the path of the car. Such a situation is quite common since truck drivers have difficulty seeing vehicles near their right front wheels. What is more likely is that the car moved into the truck’s lane and the truck driver steered, or was deflected, into the portable concrete barrier. But what would a heavy truck be doing in the left lane prior to the collision? Or was the truck initially in the middle lane and did the truck driver steer there in an attempt to avoid the car? Possible.
Even though most vehicles are now equipped with event data recorders (“Black Boxes”) in instances like these, where the contact is over a prolonged time period, there may not be a “wakening” of the system such that collision data may not become stored in the car’s recorder. Similarly the existence of event data in heavy trucks is more rare and more difficult to extract due to the specialized equipment that is required.
The OPP reported that there were minor injuries as a result of this incident and it might not even be reported by official news agencies. But even reporting by official news agencies will not contain the important information about what caused the collision and what led to its heightened consequences. For example, if all went well, the truck should have been pushed, or steered, against the wall of the barrier and it should have come to a stop in an upright position. But that is not what happened. The truck went over the barrier and rolled over. Yes, the consequences appear to have been minimized as the injuries were light. But what if the truck was carrying propane, a tank ruptured during the rollover, and there was a massive explosion? Would we be talking about the minimal consequences? Not likely.
Why did these to vehicles collide? Did the white car move suddenly into the truck’s path? That is an important question that cannot be answered based on the minimal evidence provided by the three photos. But there will be speculations. Not just by us, but by many. And some of those speculations will be totally off base. Lack of quality information does not stop persons from speculating, it only increases the magnitude of the error in the public’s understanding. And that is not helpful. A few words of explanation by police would not do any harm in their progress toward charges but could go a long way toward providing an understanding, and education, by the general public.
Strange OPP Twitter Message Regarding Fatal QEW Rear-End Impact
With no explanation the OPP posted some additional photos with respect to a dated fatal impact on the QEW that occurred last October 30, 2020. While this may not appear to be significant, the additional photos reveal something that was not revealed in the original news media accounts.
Originally, news media reported on October 30, 2020 that a school bus had been involved in a multi-vehicle fatal collision on the QEW near Ford Drive in Oakville. The focus of the attention was on the school bus in which no one was injured. Almost as an aside, the news media then reported that someone was killed in another vehicle, but minimal details were provided. A photo was attached showing a distant view of the school bus. Then another photo was shown with a dump truck and blue tarp placed over something in front of the truck. The news article mentioned that a vehicle had been “pinned under a gravel hauler” but no additional information was provided with respect to what kind of collision was involved or if someone died in the “pinned” vehicle.
Then on April 23, 2021, for no apparent reason, the OPP Twitter account re-displayed its reports of the incident from October 30, 2020. These reports indicated the following:
Update: Two separate collisions involved in this incident. The first crash involved a school bus, pick-up truck and a van that resulted in minor injuries. The school bus driver was charged with Careless Driving. The 2nd collision occurred seconds later involving a dump truck, transport truck and car. 29 year old Melissa PRIMOK from Toronto was killed in the crash. The driver of the dump truck Ronald RICKERT, 62 from Caledon is charged with: Crim Neg cause death and additional CMV charges.
This description was accompanied by three photos that were not previously submitted. These photos are shown below.
What these photos show is that a passenger car has been literally crushed between two heavy trucks. The extent of the crush is one of the worst ever recorded in over 40 years of our evaluation of thousands of collisions. It is also revealing that the dump truck that impacted the car was hauling a pup trailer. This is important information that was never revealed in the original descriptions of the incident to the public. No emphasis was provided by either the news media nor the investigating police that would educate the public about the dangers of such collisions where traffic is coming to a stop on an expressway. Regrettably, the young woman who was killed is just another statistic amongst numerous ones who have since followed. The cause of the collision was indicated in the original reporting as “unknown”. And since that time no further update was provided to inform the public.
This is the kind of process that does nothing to improve the public’s safety. Information that could, and should, have been used to inform and educate the public has been kept in hiding for no reasonable purpose except for secrecy itself. Yet this lack of education will lead to future tragedies for no useful purpose.
What were the factors that led to the extreme result in specific instance? We want to blame the driver of the dump truck but do we know? Why was this impact so severe? How much would new technology such as Automatic Emergency Braking help to prevent such tragedies? If the public was properly informed about these issues would momentum be developed that would increase the likelihood of changes being implemented? Sadly these are squandered opportunities that will revisit some future families.
Final Results From School Bus Motion Testing
Analysis of recent testing of school bus motions has now been completed. A total of six testing sessions were completed along various routes in London, Ontario noted below:
- March 4, 202; GMC 18 Passenger School Bus driven along Wharncliffe Road route.
- March 4, 2021; GMC 18-Passenger School Bus driven along Wellington Road route.
- March 25, 2021; International Full-Size School Bus driven along Southdale Road route.
- March 25, 2021; International Full-Size School Bus driven along Exeter Road route.
- March 26, 2021, International Full-size School Bus driven along Southdale Road route.
- March 26, 2021; International Full-Size School Bus driven along Exeter Road route.
Three previous articles were posted to the Gorski Consulting website discussing the results from the first three sessions:
April 5, 2021: Testing of School Bus Response to Irregular Road Surface Conditions
April 13, 2021: GMC 18-Passenger School Bus Testing on Wellington Road in London
April 15, 2021: Preliminary Comparison of Full Size School Bus Motions To Other Vehicles
Now analysis has been completed on the last three sessions. The present article will summarize the results from all six sessions.
The results from the six sessions are shown in the following tables and charts. For each session a table is presented describing the actions of the bus along each 30-second road segment, the bus speed, and the bus motions in terms of the Longitudinal and Lateral motion. A bar chart of vehicle motions is also presented for each session.
1. March 4, 2021: GMC 18-Passenger Bus on Wharncliffe Road Route
2. March 4, 2021: GMC 18-Passenger School Bus on Wellington Road Route
3. March 25, 2021: International Full-Size School Bus on Southdale Road Route
4. March 25, 2021: International Full-Size School Bus on Exeter Road Route
5. March 26-21: International Full-Size School Bus on Southdale Road Route
6. March 26, 2021: International Full-Size School Bus on Exeter Road Route
Discussion
Gorski Consulting has been gathering data of road conditions for the past seven years. The sensors of an iPhone have been used to capture a wide variety of parameters. Two parameters were chosen for display 1) Rate of Longitudinal Rotation and 2) Rate of Lateral Rotation of a test vehicle. It was reasoned that the rotation, or motion, of a vehicle is caused by its reaction to the conditions of a road surface. So a greater motion would indicate a rougher surface and therefore a surface which is of worse condition.
A webpage on the Gorski Consulting website called Road Data contains the results of testing from a large number of roads in Southern Ontario. Most of this testing was done using a 2007 Buick Allure passenger car. Although it was found that the methodology was reliable there was always a question whether a test vehicle of a completely different structure might produce very different or even unreliable data. Recently access was gained to school buses and it was decided that the road testing methodology would be used to see what differences might occur in the data.
The data presented here demonstrates the reliability of the test methods. It demonstrates that, even vehicles of vastly differing sizes and structures, can be used in documenting the condition of road surfaces.
A vast percentage of the population now has possession of smartphones. On the negative side, the designers of these devices have installed sensors that record intricate details about an owner’s actions and habits. On the positive side, such technology can be used to benefit society when used for ethical purposes such as detecting road safety problems. The gathering of vehicle motion data provides a cheap method of providing the necessary vigilance of road conditions to whoever wishes to use it. It could be used by municipalities as a quick way to spot safety problems and make corrections. However it can also be used by any member of the public.
The cost of the hardware to perform the testing is minimal. A functioning test vehicle is required and most persons already possess a motor vehicle. A smartphone is also available to almost everyone. A video camera is required but nothing is needed that cannot be purchased for under $100 dollars. A computer is required and that is available to almost anyone. Video-editing software is required but that can easily be purchased for about $100 dollars. And that is all. With a little bit of training anyone can gather and analyze the condition of road systems in an objective manner.
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