Drivers Beware – Road Data Shows Important Differences in 400 Series Highways in Southwestern Ontario

Drivers in Ontario have an objective way of comparing the safety of road surfaces. In the most recent series of testing, Gorski Consulting has compared the surfaces of Highway 401 and 402 with interesting, and differing, results.

The testing involved driving a test vehicle along each highway and documenting the amount of disturbance of the vehicle motion. The “Lateral Rotation” or sideways motion, and “Longitudinal Rotation”, or forward/back motion were sensed. This data was collected at 30 second intervals or, at highway speed (110 km/h), for approximately 900-metre distances. The averages of these motions were obtained and these will be reported.

It had been previously noted that vehicle motions under 0.0200 radians per second indicate a good surface, values between 0.0200 and 0.0500 indicate varying degrees of danger that could be hiding a local safety problem, and values above 0.0500 indicate that major road surface problems likely exist throughout the tested road segment. However there are other, complicating factors. When road surfaces become slippery due to rain, snow or ice there are greater chances of causing loss-of-control because of the lower tire force. There are also issues of speed of a vehicle and the traffic volume. Thus motions caused to a vehicle travelling at high speed are of greater concern even though the distrubed motion is lower. Similarly roads that have high traffic volumes have a greater chance of causing loss-of-control incidents simply because there are more opportunities available. The results of pervious testing have been uploaded to the Road Data page of the Gorski Consulting website.

The results of the most recent testing on Highways 401 and 402 are summarized here in a set of three charts, shown below. The first chart shows the data travelling westbound on Highway 401 from London to Tilbury. The second chart shows the data travelling eastbound on Highway 402 from Strathroy to London. The third chart shows the data from travelling westbound from London to Strathroy. Discontinuities in the Highway 401 data are because not all the collected data was analysed because there was too much data and it would be too time-consuming to analyse it all; thus various areas of the highway are shown in the chart.

Even without discussing the details of the charts, a simple, visual, comparison of the magnitude of the peaks in the data should demonstrate the large differences in the road segments.

The differences can be noted in numeric form by summarizing the lateral and longitudinal data for all the road segments on each highway as shown below.

The data for westbound Highway 401 indicates a suface that is generally in good condition although we previously reported that local problems exist. In an earlier article we used the example of a large disturbance in motion that occurred near the Merllin Road overpass, west of Chatham, Ontario.

The data for eastbound Hwy 402 show elevated values of lateral rotation. In particular the segment between 1.425 and 2.342 kilometres east of the Scotchmere Drive overpass provided readings of: Lateral Rotation = 0.0239, Longitudinal Rotation = 0.0156. While these values may not be alarming for low-speed, low-volume roads, their existence on this high-speed expressway should necessitate explanations.

However the real problems become apparent when examining the data for westbound travel on Highway 402. In three of the road segments the lateral rotation rose above 0.0300. Specifically, at the road segment approaching the Olde Drive overpass and for approximately 674 metres west of that overpass, the average lateral rotation was 0.0446. Again, this is a value that should be of some concern because it was obtained on a high-speed expressway rather than just on a low-speed urban road.

The three figures below show the condition of the westbound lanes of if Highway 402 on approach to the Olde Drive overpass as well as justs past it. These photos were taken on May 21, 2019. Clearly the lanes are visibly in poor condition.

While some patching has been conducted there are dangerous areas of missing asphalt located along the lane-dividing line which would cause problems when drivers attempt to change lanes. The collected data does not demonstrate this danger because the test vehicle did not conduct lane changes at the time of the testing.

In comparison, the photo below shows an example of the type of surface that produced low levels of test-vehicle disturbance. This photo shows the eastbound lanes of Highway 402 just east of Centre Road where the surface has been freshly re-paved. This segment of highway produced the following data: Lateral Rotation = 0.0109, Longitudinal Rotation = 0067. This is not surprizing and it demonstrates the validity of the testing methods.

The travelling public is kept unaware of these important differences in road surface conditons. When a vehicle loss-of-control occurs resulting in a collision there is no mention by police or the official news media about the conditions of the road surface and if it played a role in the incident. An important fact is the police are not experienced in recognizing dangerous road surfaces nor do they have any training or equipment to measure the extent of road surface problems. These facts result in the existence of dangerous conditions that are not recognized and continue to pose hidden safety problems to the travelling public.