This view is taken from cyclist passing observation #2 on April 14, 2023 on Colborne Street in London Ontario. This is a display from a Premiere Project combining the views from 5 cameras. This is the method used to analyze the passing motions of cyclists by motor vehicles.

Documentation of motor vehicles passing cyclists on Colborne Street in London Ontario is a time consuming affair. Yet such data may help to clarify how cyclists are struck and what actions may be needed to prevent such occurrences.

As reported in previous articles on this Gorski Consulting website, efforts have been made to gather instances where cyclists are passed by motor vehicles at the site of Colborne Street just north of St James Street in London, Ontario. After 3 video sessions on April 12, April 14 and June 8, 2023, a set of 14 cyclist observations were made where these cyclists were passed from behind by motor vehicles. A table of these occurrences was shown in previous articles and is displayed once more below.

We began detailed descriptions of these instances in a previous article published on July 22, 2023. The focus of that article was the first passing motion shown in the above table. The observation labelled “Apr 14-1” which involved a white car passing a cyclist just north of the 50-metre observation zone. Since the passing motion occurred outside of the range of the video cameras there was less relevant information that could be passed on about the characteristics of the motion.

The present article will now focus on the second observation (“Apr 14-2”) wherein a cyclist was passed by a white minivan in the vicinity of the 5 and 10-metre markers of the 50-metre site. Because this occurred within the range of most video cameras we are able to provide more useful information.

The table below shows the travel path of the cycle as it passed each of the 5-metre markers between the Zero marker and the 50-metre marker. This data shows that, in general, the cycle stayed very close to the concrete gutter of the lane. On average its position was 0.45 metres west of the concrete gutter.

The figure at the top of this article shows the position of the cyclist at timecode 00;15;52;24. That view was looking northward. The same time frame is shown in the figure below except that the view is looking southward. What we are seeing in both figures is that the front tire of the subject cycle is crossing the “Zero marker” which is at the south end of the 50-metre zone of observation. What is possible to see in the figure below is that a white minivan is approaching the cyclist from the rear and that a passing motion is about to take place.

The next figure below shows the cycle as its front tire is crossing the 5-metre marker. Here we can also see that the white minivan is just behind the cycle. The views from four other video cameras have been minimized and are shown at the bottom of the figure.

The next figure below is at the same time frame as the figure above but it is a view looking southward. We can see that as the van is about to make its passing motion its left side tires have crossed over the centre-line of the road. There is no opposing (southbound) traffic so the driver of the minivan can easily cross the centre-line without being concerned with interfering with opposing traffic. Such a circumstance does not always exist. At times a driver may decide to pass a cyclist and then discovers that he/she misjudged the speed of opposing traffic and entrance into the opposing lane becomes risky.

In the next figure below we see the situation as the right front tire of the minivan crosses over the 5-metre marker. At this time the outer edge of the right front tire is located about 2.05 metres west of the concrete gutter of the northbound lane. Meanwhile it can also be seen that the cycle is located just north of the 5-metre marker and it is about 0.35 metres west of the concrete gutter.

In the next figure below we see the scenario when the front tire of the cycle crosses the 10-metre marker. Note that the left-rear tire of the minivan is west of the roadway centreline yet it also appears to show that the minivan is at an angle to the length of the road and it is being steered back into the northbound lane. This is at a time when the minivan is side-by-side with the cycle. This can be a complicated situation. If opposing traffic exists the minivan driver may be forced to steer back into the northbound lane earlier than initially intended. The speed of the cyclist is also a complication since the passing motion can be completed earlier when the cycle is travelling slowly. If the minivan driver misjudges the speed of the cycle it is possible that steering back into the northbound lane could interfere with the travel path of the cyclist.

In the next frame below we see the situation as the right front tire of the minivan crosses the 25-metre marker. At this time the right front tire is about 1.6 metres west of the concrete gutter whereas, less than 2 seconds earlier, it was over 2 metres west of the gutter. So the van has moved substantially to right, back into the northbound lane. At the same time we can see that the cyclist is positioned approximately halfway between the 15 and 20-metre markers.

In the next figure we see the scenario when the cycle reaches the 20-metre marker. At this time the right front tire of the minivan is crossing the 30-metre marker. The minivan has now fully returned into the northbound lane.

In the figure below we see that the front tire of the cycle crossing the 25-metre marker at the timecode 00;15;56;43. At the same time the rear end of the minivan is just crossing the 40-metre marker.

In the figure below we can see the right front tire of the minivan passing the 50-metre marker and its outer edge is located 1.00 metres west of the concrete gutter. This view also shows the cycle which is passing the 30-metre marker. So the minivan has moved over 1.00 to the right in comparison to its position few seconds earlier.

In the final figure below we see the front tire of the cycle passing the 50-Metrre marker at timecode 00;16;00;55. At this time the front wheel is located about 0.40 metres west of the concrete gutter.

Analysis and Discussion

While much concern is expressed by many about the number of times that cyclists are struck while being passed by motor vehicles, little or nothing has been done to study such scenarios in objective detail to understand what factors may be at play. In most instances where a significant injury or death has resulted police attend the collision, close the roadway and complete a reconstruction of the incident. Rarely is it revealed to anyone that the results of those police reconstructions are never made available to the public. Any objective analysis and understanding of such an incident is permanently lost and allowed to repeat itself because nothing is learned from the tragedy. The only way of obtaining any useful objective evidence is to conduct observations of naturalistic behaviours such as is being done in this present article.

By observing the timecodes when the cyclist and minivan pass by the various roadway markers we are able to identify important information such as the speed of the vehicles, their lateral locations on the road and their relationship to each other.

For example we can examine the speed of the cyclist. At timecode 00;15;52;24 the cycle is crossing the Zero marker. At timecode 00;15;56;43 the cycle is passing the 25-metre marker. Thus in 4.32 seconds the cycle has travelled 25 metres or at an average speed of 5.79 metres per second or about 20.83 km/h. That is slightly higher than the typical riding speed of an average cyclist.

Next we can examine the speed of the cyclist in the second part of its travel, between the 25 and 50-metre markers. The cycle crosses the 25-metre marker at 00;15;56;43 and it crosses the 50-metre marker at 00;16;00;55. So it has travelled 25 metres in about 4.2 seconds, or 5.95 metres per second or 21.43 km/h.

Similarly we can examine the speed of the minivan. The van crosses the Zero marker at 00;15;53;06 and it crosses the 25-metre marker at 00;15;55;27. Thus the minivan travelled the first 25 metres in 2.35 seconds, or 10.64 metres per second or 38.30 km/h. Then it crossed the 50-metre marker at 00;15;57;42, so it took 2.25 seconds to travel the second distance of 25 metres. The minivan’s average speed in the second half of the 50 metre distance was 11.11 metres per second or 40.0 km/h.

So the minivan’s speed was a little less than 20 km/h higher than the cycle’s speed. This would mean that the passing motion had to occur over a longer time than if the difference in the speeds of the vehicles was greater.

This review has shown that the minivan driver passed the cyclist when the right side of the van was about 2.05 metres from the concrete gutter. And the cyclist remained riding close to the gutter with an average of only 0.45 metres west of the gutter.

According to page 15 of Book 18 (June 2021 version) the design dimensions of various cycles are shown in the figure below.

The physical width of a cycle is to be assumed to be about 0.75 metres. Thus in our example, if the centre of the cycle is at 0.45 metres west of the concrete gutter we need to add half of the 0.75 metres to determine where the cycle’s left side might be, It would be 0.45 + 0.38 = 0.83 metres west of the concrete gutter.

And we also know that the outer edge of the right front tire of the minivan does not represent the actual furthest extent of its structure to the right. Often it is add-ons such as the right exterior mirror that determine the full extent of the minivan’s structure. We have not proceeded to find out how far the right edge of the exterior mirror might protrude beyond the right edge of the tire. However, for now, we might use a value such as 0.30 metres. Thus the extent of the minivan’s protrusion to the right would be reduced from the 2.05 metres to about 1.75 metres west of the concrete gutter. So using this approximation we might say that the lateral distance between the right side of the minivan and the left side of the cycle would be about 1.75 metres minus the 0.83 metres, or about 0.92 metres. Provincial regulations state that a passing motor vehicle must stay about 1 metre away from the cycle it is passing so one might consider that the minivan was not fully 1 metre away from the cycle, as required. And we can consider that the cycle was riding close to the gutter while the average from our observations is about 0.71 metres west of the concrete curb. It can be seen that even with a fairly wide northbound lane it would be a challenge for the driver of a motor vehicle to stay within the northbound lane and still pass a cyclist according to the requirements of provincial regulations. The vehicle would be forced to ride into the opposing lane and that might not always be possible if opposing traffic exists. So the driver must be selective and alert as to when to chose the proper moment to pass a cyclist.

These are the kinds of understanding that become possible when conducting naturalistic observations of passing motions of cyclists. While this is time consuming it also produces unbiased, objective data that can help the general public in understanding the details of these events. While we all like to express our hard felt opinions it is through reference to this objective data that our opinions can be grounded in reasonable expectations.