Poor road conditions can lead to collisions. But what is a poor road condition? Gorski Consulting has been conducting testing on various roads in Southern Ontario to provide an answer to that question. Recently a roadway that contained some of the worst conditions was re-paved. This provided an opportunity to demonstrate how much of an improvement re-paving can make. This article will focus on the roadway, Sunningdale Road in London, Ontario.

In 2014 Gorski Consulting conducting testing on a number of roads and highways in London and South-Western Ontario. One of those roads was the 2.4 kilometre distance of Sunningdale Road between Clarke Rd and Highbury Ave on the north-eastern edge of London, Ontario. The testing was to document the extent of upheaval caused in the motion of a test vehicle travelling over those roadways.The figure below shows some of those roads where testing was performed.

The location of sites in London and to its south-west where testing was performed in February of 2015.

The testing involved driving a vehicle equipped with multiple video cameras through the roadways. An App (Sensorlog) loaded on a iPhone was set-up to document the vehicle’s motion. Part of the gathered data included the lateral and longitudinal motion of the vehicle. The figure below shows the results of that testing.

This chart shows that the longitudinal and lateral motion of the test vehicle was much higher while driving along Sunningdale Road compared to any of the other sites were testing was performed.

The above chart shows that the motion of the test vehicle was much greater along the Sunningdale Road site as compared to any of the other highways where data was obtained. The numerical values shown in the chart describe the motion as a “rotation” about the lateral and longitudinal axes of the vehicle. This rotation is in the form of “radians-per-second”. One radian is equal to 57.3 degrees. So a value such as 0.0500 rad/sec is equal to about 2.865 degrees per second. For vehicle stability the lateral motion is often the most critical because it can lead to a yawing of the vehicle. Yaw is the rotation that occurs about a vehicle’s vertical axis and it is the motion that precedes vehicle loss-of-control and rollover. Because a vehicle motion can be like a pendulum, motions to the left and right average out to be zero and therefore displaying those values is not meaningful. It was decided that taking the standard deviation of that motion provides a proper indication of its magnitude. It has been determined from previous testing that the quality of roadways can be categorized into three primary groupings

Values below 0.0200 = A good quality of roadway with no major safety problems.

0.0200 to 0.0500 = A roadway that is in relatively good condition in the vicinity of 0.0200 rad/sec but likely contains some safety problems, along some portions of the tested road segment, as the value approaches 0.0400 and toward 0.0500 rad/sec.

Greater than 0.0500 =  A roadway that contains safety related concerns through a substantial portion of the tested road segment.

Looking at the above chart, Sunningdale Road contained levels of lateral motion that were above the critical level of 0.0500 rad/sec. No other roadway showed that magnitude of induced motion in the test vehicle.

A substantial amount of testing was done since the testing shown in the above chart. This has revealed, for example, that the vehicle motion is dependent on the speed of the test vehicle. Not surprisingly, the vehicle motion is higher when the vehicle is travelling over the same surface at a faster speed. Interestingly the relationship seems to be more prominent in lateral motion than it is in longitudinal motion. So one preliminary conclusion might suggest that speed could be important in loss-of-control collisions because, as the speed increases, the lateral motion increases, and the tire force becomes more divergent between the left and right side tires. This leads to yaw and loss-of-control collisions.

A few years before the testing shown in the above chart the condition of Sunningdale was even worse than what the data shows. Some of those conditions are shown in the photos below.

An example of a rupture in the surface of Sunningdale Road in February of 2011 before the surface was repaved in 2012.


An example of a rupture shows a vertical drop in the surface of almost 3 inches (7 centimetres).

The shadow of the carpenter’s level is the best indicator of the extent of depression of the surface of Sunningdale Road in this photo taken on February 23, 2011.

In 2012 parts of the roadway became re-paved in the areas where the conditions were the worst. So the data in the above chart does not illustrate just how bad the situation was before that re-paving. In fact school buses regularly used this road segment and videotape taken before 2012 showed how these buses were being bounced around, to the point of possibly rolling over, just from riding over the very large ruts and depressions.

It was fortuitous that in the summer of 2019 this segment of Sunningdale Road between Clarke Road and Highbury Ave was re-paved again. Not only were the worst portions re-paved but the full length of the segment was repaved. Upon driving on the re-paved surface it was apparent that the safety issues were finally corrected. This re-paving provided an opportunity for further testing to show how effective the re-paving was in reducing vehicle motions. Thus shortly after the re-paving, on July 21, 2019, Gorski Consulting returned to the site and performed another round of testing, similar to what was performed in 2014.

View looking westbound on Sunningdale Road on July 11, 2019, shortly after the surface was re-paved.

The table below shows the results of the testing from February, 2014 when the original testing was performed, and July 21, 2019, after the surface of Sunningdale Road had been re-paved. As usual the numbers are the standard deviation in the lateral rotation of the test vehicle. In other words we are looking at the amount of sideways motion of the test vehicle.

Note that the relationship between speed and vehicle motion still holds true after the re-paving. As the test vehicle travels faster the lateral (sideways) motion increases.

What should be remarkable however is the degree to which the lateral motion has been extinguished after the re-paving. Before the re-paving, at 80 km/h the lateral motion was 0.0479 (westbound) and 0.0532 (eastbound). But after the re-paving the motion drops to 0.0184 (westbound) and 0.0172 (eastbound). This is a massive difference in the motion of the vehicle. It not only explains how re-paving can improve the safety of a roadway but it also helps to illuminate how poor the road conditions were on Sunningdale Road in 2014, even though the worst conditions were removed in the re-paving of 2012. Drivers were subjected to this “hell on earth” for a number of years without much public outcry. Why such conditions are allowed to exist for such prolonged times is often a function of poor communications passed onto the public by police and city staff who see little obligation to report and act on poor road conditions.

Police are not trained to understand the relationship between poor road conditions and collision causation. Although they may periodically conduct skid tests at collision sites those are used to estimate the speed of a collision-involved vehicle and to determine if charges for speeding should be applied. Police also have no way of determining whether ruts, depressions or undulations are of sufficient magnitude that they should be viewed as a cause in a loss-of-control collision. This makes the validity of police records questionable. Yet many decisions about public safety are made based on the assumption that police collision data is unquestionably accurate.

The Canadian Automobile Association (CAA) runs an annual “Worst Roads” campaign where the public can submit their choice of roads meritting the classification of “Worst Road” in Ontario. But such choices are based on subjective opinion and there is no objective analysis to determine how one road compares to the next.

Minimum Maintenance Standards (MMS) have been developed in the Province of Ontario by defendants in civil suits (Municipalities and the Ontario Ministry of Transportation). The purpose of these standards is to protect these defendants from civil liability. Many of these standards are so weak that they do not provide for essential driver protection. As an example, a “Surface Discontinuity” or vertical difference in road surface must be at least 5 centimetres (2 inches) before there is a requirement for its repair. Depending on the speed of a vehicle, suspension and tire characteristics and how its tires contact such a vertical wall the results can be catastrophic or insignificant, without much legal recourse available to the driver.

In other instances municipalities conduct secret testing of the road surface friction and fail to inform the public when such friction falls below acceptable standards. This was highlighted recently in Hamilton, Ontario when a report of substandard friction data became “lost” and then re-found several years later, leading to a 250 million class action lawsuit. A spokesperson for the City of Hamilton, Jasmine Graham, stated that “there are no set Canadian or provincial friction standards, and the Ministry of Transportation’s specifications are not clear”.

In this realm of confusion, secrecy and deceit, the public is treated like rows of mushrooms in an isolated greenhouse, kept in the dark and fed manure, as the saying goes. Technical reports and research that is in the hands of Municipalities and Ontario’s Ministry of Transportation are kept secret even though they are paid for by public taxes and their content may expose important safety issues. Furthermore independent testing, such as that conducted by Gorski Consulting is often met with resistance as officials believe that they have a monopoly on conducting testing on public roads. Friction testing for example would be impossible to conduct independently without police being called to stop any such activities. The advantage of the vehicle motion testing conducted by Gorski Consulting is that it cannot be prevented because it involves the normal travel of the test vehicle, no different than any other vehicle that has the right to use public roads.

The result of the Gorski Consulting tests is that the public is given objective information about the quality of road conditions independent of those who would wish to have that information hidden. While additional information such as friction testing cannot be done there is sufficient information contained in the Gorski testing to make it useful in comparing the safety conditions of one roadway to another. Over the years a Road Data database has been uploaded to the Gorski Consulting website which provides details of the testing along many roads in Southern Ontario. The public, or anyone, is free to examine the data and draw conclusions as they wish.

There is additional data that has been gathered that would be too voluminous to upload to the website. This includes video footage and parameters such as accelerations and test vehicle angles with respect the three vehicle axes (x,y,z). The angle data is useful to explore issues such as the cross-slopes and superelevations of roadways and the downslopes of roadsides such as shoulders. All this data is obtained because the iPhone is such a successful spying technology such that the actions of persons carrying an iPhone can be easily determined by anyone with access to the data. So while the iPhone can be used for malicious purposes it can also be used for ethical purposes as well.

The testing by Gorski Consulting is totally independent of any outside interference or funding. Not many firms or research institutions can make that claim. In these days when research and reports are paid for by entities who expect a certain result, there is no such connection in the Gorski research results. No public money has ever been delivered for our studies and our retainments on individual collision reconstruction assignments are narrowly focused on those assignments, never filtering over into the independent research that we do for the general benefit of our community.