This view is of Premiere Project created to examine the details by which motor vehicles pass cyclists on Colborne St just north of St James St in London Ontario. The cyclist is shown here entering a 50-metre zone of markers which document details about the cyclist’s actions prior to a passing motion by white car.

Stress, anger and accusations abound these days as cyclists find themselves vulnerable to being struck by vehicles operated by seemingly uncaring drivers. While impacts occur it is rare that anyone can state with any degree of accuracy how and why the impacts occur. For example the details of investigations conducted by police are never available for the public’s consideration. So, while injuries and deaths occur, nothing of any usefulness is available to be used to educate both cyclists and motor vehicle drivers as to how to avoid these incidents.

Gorski Consulting has been involved in the reconstruction of many motor vehicle collisions, some of which have involved serious cyclist collisions. As the principal of the firm, Zygmunt Gorski, is now in the process of retiring. Yet the methods of detailed analysis that were developed over many years of study can be applied to provide some help to the general public rather than to paying clients. As such Gorski Consulting has recently been involved in a number of documentations focused on improving the public’s understanding of collisions and how they occur. With the increasing numbers of cyclists riding on roadways of varying levels of safety, Gorski Consulting has commenced a number of studies focused on providing detailed, objective and unbiased data that will be available for anyone to evaluate and analyse.

One of our projects has involved a section of Colborne Street in London Ontario where the City of London is preparing to create a painted cycling lane north of Oxford Street. Some concern has been expressed by some cyclists that painted cycling lanes do not provide the necessary level of protection and that the cycling lane should be one with a protective barrier between cyclists and motor vehicle traffic. Because of such concerns we determined that this would be a good opportunity to conduct some detailed observations of how cyclists and motor vehicles interact at the site.

In the fall of 2022 Gorski Consulting commenced three sessions of observations with the use of synchronized, multiple video cameras. These efforts resulted in calculations of vehicle speeds and volumes and these data were compared to the recommendations of Book 18 of the Ontario Traffic Manual. It was felt however that this study was not enough.

It was decided that a very useful study would involve documenting the lateral travel paths of motor vehicles and cyclists and they passed through an observation area of 50 metres. Within this zone a matrix of markers was placed at 5-metre intervals and at each station additional markers were placed lateral to the northbound lane. These efforts would provide objective data regarding how cyclists and motor vehicles interact before a painted cycling lane is created. Three such sessions were conducted on April 12, April 14 and on June 8, 2023. Once the City of London created the painted cycling lane it was deemed that a second set of sessions would capture if and how the lateral paths of all traffic units had changed.

At present our analysis of the video projects from the three video sessions has allowed the capturing of a number of northbound cyclists. Our goal was to examine these instances and take a subset of those where motor vehicle passing motions occurred. As a result fourteen observations were identified where such passing motions were in effect and these observations are shown in the table below.

Note that no passing observations were identified from the first video session of April 12, 2023. Six observations were found from the video session on April 14, 2023 and another eight observations were captured from the June 8, 2023 session.

Detailed study of these actions is complicated and time-consuming. It requires examining views from several video projects that contain different mixes of video cameras since not all views can be crowded into a single project. Yet the results can be quite enlightening to those who may be interested. Thus in this article we will focus on a single observation of a passing motion to show what can be learned. The observation we will focus on is the first one in the above table. Even though a passing motion did not occur with the 50-metre observations zone we can see how the white car approached the cyclist, what speeds were involved and other interesting facts.

Exploration of a Cyclist Passing Motion

We begin this study by looking at the contents of the Premiere video project containing views from five video cameras. The view at the upper left shows that a northbound cyclist is seen crossing the Zero marker at the timecode 00;11;44;49.

The table below shows how the cyclist moved through the site as he passed by each of the 5-metre markers. The numbers are with respect to the edge of the east concrete gutter which is the Zero for all lateral positions. So, at the Zero marker the cycle’ front tire passed through at 1.00 metres west of that concrete gutter. One can see that the cyclist then started to ride a little closer to the concrete gutter as we see values such ass 0.80, 0.70 and even 0.65 at the 50-metre marker. On average the cycle rode about 0.78 metres west of the concrete gutter.

The next figure shows the scenario at 00;11;50;11 which shows an elapsed time of 5.37 seconds in which the cyclist has managed to reach the 30-metre marker. Simple calculations indicate that the cyclist’s average during this time must be about 20.11 km/h.

The next figure shows that a white car makes a left turn from eastbound St James Street and begins to travel northbound on Colborne. At this same time the cyclist has managed to reach the 40-metre marker.

In the next figure below we see that the white car has reached the Zero marker at a timecode of 00;11;52;14. Looking at the position of the car’s right front tire we can see that it is riding over the 1.00 metre marker. In other words the car is 1.00 metres to the west of the concrete gutter. We will want to observe if, and how, this lateral position of the car changes as the vehicle approaches the cyclist.

In the next figure we see that the cyclist has reached the 50-metre marker at a timecode of 00;11;53;30. The 50-metre marker represents the end of the zone of observation so will have little information about what happens after the vehicles exit this zone. However we can calculate the average speed of the cyclist between the 30 and 50-metre markers and this happens to be about 21.69 km/h, or just slightly faster than the 20.11 km/h that the cyclist was travelling as he entered the area of observation.

Meanwhile we can also calculate the speed of the white car. Below we can see it crossing the 20-metre marker at timecode 00;11;53;47. And we know that it crossed the Zero marker at timecode 00;11;52;14. Thus it took the car 1.55 seconds to travel the 20 metres and its average speed was 46.45 km/h.

We also note in the figure below that the white car passes the 50-metre marker at timecode 00;11;55;53. So the car’s average speed between the 20 and 50-metre markers was 51.43 km/h. At the time that the car passes the 50-metre marker its right front tire crosses at about 1.0 metres from the concrete gutter.

By zooming in on the northward view from the camera at the Zero marker we are able to see the lateral position of the white car at the timecode of 00;11;55;53 and this is when the car is crossing the 50-metre marker. The view below shows that the white car is at a slight angle to the west and therefore it is likely proceeding to pass the cyclist.

Although we do not know the precise location of the cyclist when the white car is at the 50-metre marker we can extrapolate from the fact that between the 30 and 50-metre markers its average speed was 21.69 km/h. Thus in the time that the white car travelled 30 metres in a time of 2.06 seconds.

At an average speed of 6 metres per second, in 2 seconds the cyclist would travel about 12 metres. Thus at timecode 00;11;55;30 the cyclist would in the vicinity of 62 metres north of Zero. Meanwhile at a timecode of 00;11;55;53 the white car is passing the 50-metre marker, which is about 0.38 seconds later than the time quoted for the cyclist so the car would need to be reversed by 5.4 metres in that time. The bottom line is that the cyclist would be at 62 metres and the white car would be at about 44.6 metres when the car is seen steering into the middle of the roadway in preparation to pass the cyclist. So this information gives us an idea as to when a driver might begin to steer around a cyclist who is travelling about 21.69 km/h. And this would occur when the car was about 17 to 18 metres behind the cyclist.

Even though the passing motion occurred just north of the observation area, we are still able to conduct some calculations to indicate how the passing motion develops. Looking at the rest of the observations in the table above there are several passing motions that occurred within the observation area and these will provide useful information. Because these analyses are time-consuming it requires someone to volunteer to take on this assignment, examine all the observations and then come up with some ideas as to how these cyclist versus motor vehicle interactions occur. Gorski Consulting is certainly willing to provide these video projects to anyone who would wish to pursue this research.