Blackfriars Bridge – Comparison of Dillon Consulting & Gorski Consulting Traffic Studies – Overall Traffic Volumes

This view of a cyclist turning onto the Blackfriars Bridge in London was taken on August 23, 2022 at a time when traffic studies were being conducted by Gorski Consulting and Dillon Consulting. Dillon Consulting was officially retained by the City of London while Gorski Consulting performed a study independent of the City. Results of the two studies provide some insight into how data, and the conclusions drawn from them, can vary.

In recent years considerable debate existed in London Ontario with respect to the usage of the historical Blackfriars Bridge located just northwest of the City’s downtown. While there was much opinion there was scarce data to support that opinion. As a result Gorski Consulting commenced a traffic study in the spring and summer of 2022 and its results summarized and uploaded to the Gorski Consulting website. It became known that the City also intended to conduct a long-term usage assessment of the Bridge although what form that study would take and when it would be completed was unknown.

In a report to the City of London dated May 31, 2023, Dillon Consulting reported that it had been retained by the City to conduct a long-term usage study of the Blackfriars Bridge. A brief review of the report showed that Dillon conducted its investigations through a similar time period as the Gorski investigations, both in the spring and summer of 2022. It become possible therefore to examine the findings from both studies and to explore their differences and similarities. The purpose of this present article is to begin that comparison through a review of the general traffic volumes that were documented in both studies.

Among the details reported in the Dillon Consulting report was a Table 6 summarizing their findings from an 8-hour session of observations undertaken on September 29, 2022. That table is copied below.

A somewhat similar summary table was created by Gorski Consulting and this table is copied below. The Gorski data was developed from conducting two-hour observations on five different days, thus resulting in 10 hours of observations.

The reporting of traffic by Dillon during morning and afternoon peak hours, along with a noon-time session day is a standard and accepted methodology.

The Gorski methods were slightly different in that observations were made during five different days, These days were chosen to encompass a diverse range of possible traffic patterns. On May 29, 2022 a session was conducted on a Sunday to document what differences there may be from weekday observations. The other 4 sessions were conducted on weekdays (Monday, Tuesday, Wednesday and Friday) thus allowing a further exploration of changes in traffic during the week. Diverse times of observation were also employed encompassing similar times to the Dillon observations.

Comparing motor vehicle traffic, Dillon reported that a total of 659 units were observed during their 8-hour session, or approximately 82.4 units every hour. In comparison, Gorski reported that a total of 482 units were observed during their 10-hour session, or approximately 48.2 units every hour. Thus Dillon reported at least twice as many motor vehicles per hour as the Gorski data.

With respect to cyclist volumes, the Dillon table did not provide an overall summary of the number of cyclists they observed. Instead they reported the cyclist data in separate columns showing individual motions. A summary was then provided that grouped the pedestrians and cyclists together. We summed the cyclist numbers in the various cells of the Dillon table and this showed that they observed a total of 635 cyclists. The same procedure revealed that Dillon observed 1745 pedestrians. Thus they observed a combined total of 2380 cyclists and pedestrians during the 8-hour session.

In comparison the Gorski table shows that 842 cyclists and 1017 pedestrians were observed in total of 10 hours of observation. A slightly different approach is that Gorski described a separate column of “Non Pedestrians” which encompassed traffic units of various sorts such as persons riding medical carts, e-scooters, etc. and these numbered a total of 70 observations.

Looking at these sums of cyclists and pedestrians, Dillon reported approximately 79.4 cyclists per hour whereas Gorski reported approximately 84.2 cyclists per hour. Thus, at face value, there does not appear to be a major difference in the findings. With respect to pedestrians Dillon reported approximately 218 per hour whereas Gorski reported approximately 101.7 per hour. Thus these pedestrian sums indicate a substantial difference. Dillon reported observing more than twice as many pedestrians as Gorski.


Examining the documentations that Dillon Consulting obtained on September 29, 2022, they reported about twice as many motor vehicles and pedestrians, per hour, as compared to the documentations obtained by Gorski Consulting. Cyclist volumes were approximately similar between the Dillon and Gorski studies.

The Dillon report focused on the efficiency of traffic flows in the vicinity of Blackfriars Bridge while less attention was brought to potential safety concerns at the bridge. This may be related to the scope of their assignment as defined by the City. Little information is available about that scope since the retaining letter from the City to Dillon Consulting is not available. Dillon provided a brief mention of the scope of their assignment in the Introduction segment of their report where they stated:

“Dillon was to quantify the usage of the Bridge by vehicles, pedestrians (ped.), and cyclists, and evaluate the role of the bridge in the transportation network for all users.”

In the Approach segment of their report Dillon indicated that they examined the behaviour of traffic units at the bridge:

“Dillon performed a site visit to the Bridge to observe how vehicles, pedestrians, and cyclists were using the Bridge and identify any unusual behaviour that might be occurring.”

It is unusual that Dillon Consulting did not report safety concerns at the intersection of the pedestrian crossing of the Thames Valley Parkway at the east end of the bridge. Gorski Consulting observed several obvious issues during our examinations and some were reported in articles posted on the Gorski Consulting website. A review of these issues will be made in a separate article that will be posted shortly to our website.

Officially-Invisible Cargo Carriers In London Ontario

Not everyone can see them but, like Santa Claus, there are invisible cargo carriers out there. Some cannot see these cargo carriers because of simple things like darkness of night. But many do not see them because they chose to be blind to their presence.

Much like the population of homeless persons, those transporting cargo through unorthodox means, are not officially visible. Certainly they’re not visible to politicians and officials who control the maintenance and design of roadways. Yet Gorski Consulting has managed to capture come photos of them in recent years.

In official circles the future will include large numbers of cargo bikes which ride swiftly and conveniently within a 1.5-metre-wide cycling lane. Planning and development is focused on this throughout cities like London, Ontario. In unofficial reality the situation is more complex.
Here is an example of a “cargo bike” not being ridden in a cycling lane but on a city sidewalk. The larger width of the mini-trailer means that it would likely not fit well within a 1.5-metre cycling lane.
Here a cyclist pulling a mini-trailer rides on the road but his visibility to drivers is limited because his height is below many vehicles such as the white van behind him. There are many instances where the driver of the red mini-van cannot see the cyclist because of such a blockage of view and, if the white van moves abruptly to the right the driver of the red mini-van can be faced with the appearance of the cyclist within a very short time and distance.
In this instance a man is carrying both, a chain saw and a Tim Horton’s coffee mug in the same hand, while using the other hand to steer his bicycle. He was located on a sidewalk but this poses a problem regardless of where he rides. No roadway designs can efficiently accommodate such a rider. However inquiries as to why this rider has chosen this action could result in changes to prevent an accident.

A common example is seen here where cans are being transported in a grocery cart, usually to a local beer store. Here the pedestrian is using the shared cycling lane which has no defined width. The person should be walking on the sidewalk. If he chose to walk within a cycling lane he would not fit efficiently within a 1.5-metre width of a typical cycling lane.
This person has difficulty seeing around his loaded grocery cart that is being pushed on a City street. Fines laid against such a person are blind to the understanding that this action often occurs through necessity. An alternative approach is to gain information as to why this person is carrying the cargo and whether an alternative is available, such as a different transportation device, which allows the person to achieve his needs.
In this instance a mini-trailer is being pulled by a medical scooter. When crossing over uneven terrain the loose materials are in jeopardy of falling off. Yet there in no law that states such cargo should be securely tied down like there would be with a motor vehicle. Again, an inquiry as to why this is occurring and how it could be altered is more productive than simply fining the individual.
Parking for a loaded grocery cart is a simple problem, it would seem here, where the cart is simply left in the eastbound lane of Dundas Street near English Street in east London. Such events occur when many persons live on the street and their “house” rides on these four wheels.
A very common way to transport a loaded shopping cart is to use a bicycle, as shown here. However such an arrangement would not fit within a 1.5-metre cycling lane. In this instance the transportation is occurring on a City sidewalk.
Here is another example of an overloaded shopping cart where the person cannot see ahead of the cargo and the blue cargo near the base of the cart is quite wide making it unlikely that it would fit on a sidewalk or within the narrow confines of 1.5-metre cycling lane. Here the person simply uses the right road edge for his travels. Obviously this can cause traffic problems depending on the roadway where is occurs.

Here is another example of a cyclist carrying cans, likely to a beer store. No helmet means that if he loses his balance he could experience a possible head injury. Yet carrying cargo in this fashion increases the likelihood that balance could be lost if, for example, the bag of cargo strikes something close to the sidewalk.
In this instance the cyclist is pulling a small loaded wagon with an improvised, long draw bar. Motorists do not expect a cyclist to be pulling such an object and, because the wagon is low to the ground, many motorists would not detect its presence in traffic. Again what is needed to an inquiry as to why this unorthodox procedure is used and whether a different method of transportation can be found.
In this example a medical cart is being used to pull a large garbage pail along a City sidewalk.
And in this example more cans are being transported on a sidewalk using a two-wheeled cart.
When weather conditions are not favourable these persons have placed a large umbrella over their loaded shopping car. In many instances these could be the only possessions of the individuals who could be homeless.
There are instances where dog owners will attach their pets to a harness and then attach the harness to a cart. This improvised “dog sledding” does not always result in satisfactory control of where/how the dog will pull the cart. In conditions of higher motor vehicle volumes the situation is not ideal.

The above examples show the complexity with which cargo is transported through roadways in the City of London Ontario. Many of these improvised methods of transportation are created through necessity as economically disadvantaged citizens cannot afford a more efficient method of carrying their goods. Gatherers of scrap metal, aluminum cans or other materials can sell these materials and gain some needed income. When a minimum guaranteed income is insufficient to enable persons a safe survival persons naturally improvise to survive.

As the population of homeless persons in London has mushroomed over the last few years so have the numbers of unorthodox instances of cargo transportation. Where society has failed to improve the plight of the homelessness or economically disadvantaged it must also experience complications when transportation essential to the homeless becomes a safety issue because the road system is not designed to accommodate these invisible persons. Recent discussion has focused on roads that are designed for “all ages and abilities” but this seems to be only for the visible population. Are roads to be designed only for “all ages and abilities” of “visible” persons? Or are we able to open our eyes and see everyone who uses our public roads.

Cyclist Observations in London Ontario Canada – 1st 4 Months of 2023

A balmy first two months of 2023 brought out more cyclists than normal in London Ontario. This was reversed with a colder March. Never-the-less the number of cyclists observed along London’s roads increased compared to the years 2021 and 2022.

While everyone’s thoughts are on increasing the cycling mode of transportation, little public documentation exists with respect to if and how cyclist volumes are changing. While Gorski Consulting has been documenting cyclists in London since 2013, that documentation has been more robust in the last few years. Data is now available from cyclist observations in the first four months of 2023.

Overall, 280 cyclists were documented from January through April, 2023. In that total there were 240 males, 22 females and 18 whose gender could not be determined. Of the 262 observations where gender was known the percentage of observed females was only 8.40 %. In comparison, in the whole of 2021 that percentage was 13.65 and in 2022 it was 13.11%. While the 2023 numbers appear to show a reduced female volume one needs to compare apples to apples, thus we need to look at the first 4 months of 2021 and 2022.

In the first 4 months of 2021 only 98 observations were available where gender was known. Only 11 females were documented and 87 males. This led to a female rider percentage of 11.22 %. In the first 4 months of 2022 156 observations were available where gender was known. This led to a female rider percentage of 8.97%. Compared to 2023 one might be tempted to conclude that these numbers suggest that the percentage of females riders was higher in 2021 and 2022. However we are looking at small numbers of observations and, in my view, there simply is insufficient data to draw such a conclusion at this time.

Looking at the overall observations from 2021 through to the end of April, 2023, there were 1856 observations where gender could be determined. Of those, there were 1622 males and 234 females. Thus the percentage of female riders over this larger dataset is 12.61%. This larger dataset might be more indicative that, overall, the percentage of female cyclists riding along or adjacent to the streets of London, Ontario remains quite low.

It has been suggested in various research that low female cycling could be attributed to reports by females that they feel unsafe. That my be so, however this does not explain why that percentage would appear to be lower in the first four months of each year in London. Is it possible that weather conditions might also play into this relationship? Are females also less inclined to ride cycles when the weather conditions are less favourable? It would be helpful if further research could provide more concrete conclusions.

If the cycling mode of transportation is to be increased we need the involvement of the female half of the population and we need to understand why less females appear to be riding in London and if a solution can be found to increase that percentage.

Lateral Travel Paths of Vehicles & Cyclists on Colborne St in London Ontario Canada

Many cyclists complain that motor vehicles encroach into their riding space. They also complain that painted cycling lanes do little to improve their safety. However there is no objective data available to quantify this subjective feeling of danger. For this reason Gorski Consulting has embarked on a documentation of lateral travel paths of motor vehicles and cyclists along an urban street (Colborne Street) in London, Ontario, Canada. The above table provides some preliminary results from two sessions of observations, conducted on April 12 and 14, 2023.

The “Average” column shows the distance, in metres, that the outside edge of the right front wheel of a motor vehicle was located with respect to the edge of the concrete gutter of the lane (i.e. the right edge of the lane). The “Standard Deviation” is the degree of variation in that average. For cyclists the position of the front wheel was documented. Further explanation is shown in the following figures taken from video during the testing procedures.

This view shows a typical northbound light vehicle travelling through a set of orange roadway markers in the northbound lane of Colborne Street. The markers are positioned at 5-metre intervals. Within each 5-metre position orange dots have have been painted at 20-centrimetre intervals over a width of 2 metres. As the right front tire of a vehicle crosses the dots its lateral position is noted and then averaged over a distance of 50 metres.
In this view the right front tire of an London Transit Commission (LTC) bus is seen travelling over the first set of markers. It can be seen that the outside edge of the tire is about 0.70 metres from the right edge of the lane (i.e. distance from the edge of the concrete gutter). Video cameras follow the progress of the bus as it passes through each set of markers positioned at 5-metre intervals over a distance of 50 metres.

In this view we see a northbound cyclist travelling over the first set of markers. The cycle’s front tire is crossing over the dot at 0.60 metres distance from the right edge of the lane.

Procedures like this help to provide basic data on the typical lateral travel paths of various motor vehicles and cyclists. This provides a quantitative basis for discussing the extent to which motor vehicles and cyclists may interact as cyclists are passed by the larger and wider motor vehicles. Eventually some data will be gathered as to the lateral position of motor vehicles as they pass cyclists within this 50-metre zone of testing.

The preliminary data in the above table shows that the right front tires of LTC buses typically past through a similar lateral location as the lateral paths of cyclists. Oversize vehicles in this study were comprised of slightly narrower vehicles such as over-size commercial vans, although some school buses are included in this category. The lateral travel paths of these over-size vehicles along with the paths of light vehicles appear to be located further away from the right lane edge (1.03 and 1.08 meters) than cyclists.

It is important to note however that the standard deviation of the lateral travel paths in each category provide some concern. The deviation in the lateral paths of cyclists is greater than that of the wider motor vehicles. Such information needs to be studied further.

The Colborne Street site was chosen for this study because the City of London has informed the public that it intends to create a cycling lane at this location by painting a white line to designate the edge of the cycling lane. Once such a line is painted it is expected that further documentations will take place to observe what differences there are in the travels of the vehicles and cyclists compared to the condition where no painted white line existed.

Tracking Motor Vehicle & Cyclist Lateral Paths – Preliminary Results

Tire imprints (black circles) show where orange paint has been transferred after vehicles travelled over wet orange paint. White line shows proposed edge of cycling lane (1.5 metres wide) expected to be created by City of London in near future.

Preliminary testing is being conducted by Gorski Consulting to track the lateral position of motor vehicles and cyclists within the northbound lane where a new cycling lane is proposed on Colborne Street in London, Ontario. The procedures involve the production of a matrix of painted orange dots at 5-metre intervals for a distance of 50 metres. At each 5-metre location orange dots are painted at 20-centimetre intervals commencing from the east concrete gutter and progressing up to 2 metres into the lane. Video cameras placed near each 5-metre interval capture the position of the right front tire of a motor vehicle with respect to the orange dots. For cyclists the video captures the position of the front tire.

Because motor vehicles travel at higher speeds their lateral position is not likely to change greatly over the short distance of 50 metres. Thus it is likely that the tires of motor vehicles will only be documented at the zero, 25 and 50-metre intervals. Unlike motor vehicles cyclists travel at a slow speed and thus are more likely to change their lateral position in the 50-metre distance. Also cyclists depend on differing steer angles and body positions in order to keep along a certain path and this is another reason why their paths are likely to change. Thus for cyclists their paths will likely be documented at all ten 5-metre intervals.

Given the extensive time commitment it is unlikely that the paths of all motor vehicles will be documented although that decision might change if volunteers are found to conduct these detailed observations. However It is expected that larger vehicles such as trucks and buses will be fully documented as there is likely to be few of these observations.

As an example of the type of data that is likely to be generated, the above photo shows a view, looking south in the northbound lane of Colborne Street in London, Ontario, where the testing is being done. A 5-metre interval is shown as noted by the row of orange dots at the top and bottom of the photo. As the orange paint was sprayed to produce the dots motor vehicles passed over the wet paint and then transferred the imprints onto the pavement at each revolution of the tire. Those transfers are rather faint so they have been highlighted in the photo by black circles. Additionally a white line has been produced to show the position of the future, white line of paint that is expected to be painted by the City of London sometime in the future. Through this methodology we can see where the right side tires of motor vehicles have passed with respect to the width of the future cycling lane. This visual method of showing the motor vehicle paths may not be as detailed as the numerical methods that will be employed but it is a quick demonstration of a small number of observations and what they reveal. We will be tracking the lateral positions of cyclists in the more-detailed, numerical fashion and this data will be presented in a future article when analysis is completed.

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