One Thousand Observations of Responses To Roadway Traffic Signals
Applying an accurate estimate of the delay to the expected reaction of a driver to a collision situation is an extremely important part of a collision reconstruction. Documenting driver responses to traffic signals can provide useful research data for that purpose.
Gorski Consulting has been involved in a two-year study of driver reactions to the activation of a green traffic signal. In that time 1010 observations were made, predominantly in the City of London, Ontario, Canada. The observations were made using a dash camera that was activated while stopped behind vehicles at a traffic signal as in the example shown above. The video segments were analysed to determine when the green signal became activated and how long of a delay occurred before the brake light was extinguished on a stopped vehicle.
The chart shown below is a frequency count of the number of observations, at 1/10 second intervals, from zero to 1.2 seconds delay. The “P/R” refers to “Perception Response” delay.
The above chart accounts for only 799 of the 1010 observations. The remaining observations fell outside of the chart’s range and that is an important finding.
In 236 of the 1010 observations the response delay was equal to or greater than 1.0 seconds. Conversely, in 234 of the 1010 observations the response delay was less than 0.4 seconds.
Stated another way, about 63 percent of the responses were between 0.4 and 1.2 seconds. The remaining 37 percent were either shorter or longer than this range.
It can be fairly certain that a typical driver should not be able to release a brake pedal in less than 0.4 seconds after the activation of a green signal. Therefore the 236 observations where the delay was shorter than 0.4 seconds suggests that about 24 percent of observed drivers were likely releasing their brake pedal before the traffic signal turned green. In fact the actual percentage was larger because in a number of instances vehicles were observed to be crawling forward even though the brake lights were still activated. Thus drivers were releasing their brake pedals just slightly but not enough to extinguish the brake lights.
Death of Cycling Professor – Final Results & Conclusions
This is the final in a series of four articles dealing with the death of a retired professor who died when attempting to cycle across Gainsborough Road in London, Ontario on September 5, 2020. Data has been collected to document the volume and speed motor vehicles, cyclists and pedestrians. The finalized tables are now available below.
The first table (below) shows the average speed of 585 eastbound vehicles that were videotaped while travelling within a 200 metre distance approaching the multi-sue path. The data is broken down into six 20 minute segments. These speeds include the large number of turning vehicles that existed in the first hour of documentation
We can compare the numbers of vehicles travelling straight through the site by looking at the last column “EB Straight Thru Vehs As % of All Vehs”. This shows that in the first hour the data included many vehicles that were turning onto Gainsborough from two driveways on the north side of the road. As noted previously there was some kind of commercial event taking place at an establishment on the north side of the road and this was drawing a large number of vehicles in and out of the driveways. This is why the percent of vehicles travelling straight through the site was only in the range of 65 to 80 in the first hour. However in the second hour we can see that the percentage of straight-through vehicles rose to about 92 to 98. This shows that the commercial event was completed and vehicles were no longer exiting the driveways in the second hour of videotaping. This is also reflected in the smaller number of total eastbound vehicles (91, 63 and 85) in the last hour versus the larger numbers (118, 101 and 127) in the first hour.
In terms of average speeds of eastbound vehicles, these speeds were reduced as vehicles approached the cycling path. There was also a trend for higher speeds in the second hour as the interference caused by the turning vehicles was removed.
We can recall that on the eastward approach to the site the maximum posted speed limit was 60 km/h. As eastbound vehicles approached the 200 metre marker a sign was posted indicated that the maximum speed was reduced ahead to 50 km/h. Then just before reaching the cycling path another sign indicated the maximum posted speed was 50 km/h. So drivers travelling through the site should have been reducing their speed from 60 to 50 km/h. We can see in the above table that average speeds were substantially higher than those posted maximums.
There is further reason for concern when we remove those observations where an eastbound vehicle was interfered with by other vehicles. An interfering vehicle was defined as any vehicle that was within five seconds ahead of the subject vehicle. Thus it was reasoned that a driver following such an interfering vehicle was not free to chose an independent speed. When all those observations of interference were removed from the above table the adjusted results are noted in the table below.
Comparing the data in the two tables the average speed of vehicles was increased when those 232 vehicles that travelled straight through the site and experienced no interference. This is particularly obvious in the first hour of observations where the interference caused by left-turning vehicles was present. If we look at the distance of 200 to 150 metres west of the cycling path the average speeds in the first hour were 66.14, 68.55 and 62.79 km/h as noted in the first table. But in the second table those average speeds rose to 68.08, 71.24 and 68.98 km/h. Similar results are apparent in the other distance segments.
Interference must be considered an influencing factor in the speeds of eastbound vehicles on Gainsborough Road. It is more likely that a cyclist or pedestrian might try to cross Gainsborough at times when there is no interference. In other words, it is unlikely that cyclists or pedestrians would try to cross when the gap between eastbound vehicles was five seconds or less. Thus it is important to examine the average speed of non-interfered vehicles rather than examining the total population of eastbound vehicles.
The numbers and percentages of eastbound speeding vehicles for the full two hours of documentation are summarized in the table below.
The above table shows that, out of the 232 eastbound vehicles that travelled without interference the numbers and percentage of speeders is as follows:
130 vehicles travelled at 72 km/h or greater, or 56.03 % of total
44 vehicles travelled at 80 km/h or greater, or 18.97 % of total
4 vehicles travelled at 90 km/h or greater, or 1.72 % of total
Even if the maximum posted speed was 60 km/h throughout the full distance of 200 metres west of the cycling path this would still indicate that about 19 % of non-interfered drivers chose to drive at 20 km/h or greater above the posted speed. But we know that these drivers were informed that they were approaching a 50 km/h zone thus the speed difference is even greater than 20 km/h.
These results should not be surprising. The eastbound vehicles had been travelling on a rural highway just before reaching the collision site where the posted maximum speed was 80 km/h. The collision site is just at the edge of the built up area of the City of London. The maximum speed of 60 km/h is posted at a distance of approximately 500 metres west of the cycling path. Then at approximately 250 metres a sign indicates that a maximum speed of 50 km/h is just ahead. Then within 20 metres west of the cycling path a sign indicates the 50 km/h maximum speed. However the erection of such signs does not guarantee that drivers will follow that requirement. Indeed numerous traffic studies conducted by Gorski Consulting, based on videotaped motions of vehicles, have shown that drivers do not travel at or below the speed posted on a maximum speed sign. The degree to which drivers speed through a site changes from one location to another. This is why detailed studies are needed to determine where speeding is a greater problem and if further actions to reduce speeds are necessary.
The following series of five images shows what can happen when vehicles are travelling too quickly in a area where visibility is poor. These images are frames taken from a video camera positioned on the east side of the cycling path on the north side of Gainsborough Road. The two cyclists in the images are travelling in the same (southbound) direction as the retired professor and his partner. As can be seen the female in the lead does not look toward the west while the male cyclist looks twice. Both times there is no eastbound vehicle in view. Then, as the male rider is looking forward in the last frame, a red eastbound vehicle appears just past the edge of the trees/bushes.
It is unknown how the actual collision occurred in which the professor was killed. However this is an example where the combined effect of high motor vehicle speed and poor visibility could be major causal factors.
The slope of the roadside at the path is another factor that could influence the cause of a cyclist collision. It was observed that a substantial downslope existed on the south side of Gainsborough at the roadside between the sidewalk and the edge of pavement. Slopes are an issue for recreational cyclists because they can increase or decrease a cycle’s speed. A cyclist whose physical abilities may be limited can have difficulty travelling up slopes and this can reduce their speed. Similarly down-slopes can push a cyclist into an unwanted position or make the cycle more difficult to stop.
The photos below show how slope measurements were taken on both sides of Gainsborough Road along the crossing at the cycling path. A carpenter’s level attached to a digital level was used to measure the slope in percent. In the three photos below the measurement being taken is at the south sidewalk and this gave a reading of 1.6 % downslope to the north (i.e. toward the road).
The next three photos show a similar measurement being taken of the south roadside located between the sidewalk and the edge of the roadway pavement. This reading showed a downslope of 11.6% to the north (i.e. toward the road).
As a comparison, roadway geometric design manuals for the province of Ontario recommend a maximum downslope of 12 percent for secondary roads. Thus the roadside slope is at the top of that maximum recommendation for roads driven by motor vehicles. However, cycles are not motor vehicles and they do not possess the “low rear” that can help a braking system to slow a vehicle’s motion along a downslope. The only way to reduce a cycle’s speed on a downslope is to use the cycle’s brakes. This is not ideal when approaching a busy roadway where it is important for a cyclist to stop before entering the roadway.
View looking south toward the sloped roadside between the south sidewalk and the edge of the pavement of Gainsborough Road.
Northbound cyclists, such as those from the video frame shown below, were observed to stop at the top of the downgrade, on the sidewalk, to make traffic observations before descending the downslope and crossing the road. When starting their motions from a distance away from the road they increase their travel distance and time and make themselves more vulnerable to problems if they misjudge the speed of approaching vehicles.
An example, taken from video on September 13, 2020, shows northbound cyclists stopped at the top of the downgrade while observing whether it is safe to cross Gainsborough Road. This causes a longer time and distance to cross the road and a potential safety concern.
Various riders exist on a cycling path, some of them may be elderly, some may have physical limitations and some may be small children who may be inexperienced in handling their cycle. Such limitations need to be kept in mind when considering the safety of an intersection of a cycling path with a busy road.
This example, taken from video of September 13, 2020, shows a family with small toddlers being pushed in car-like carriers. Behind them is a southbound cyclist. This demonstrates the diversity of persons that could be crossing at the multi-use path and the need to consider their safety.
Similar slope measurements were taken on the north side of Gainsborough Road and these revealed less of a concern. The sidewalk on the north side was almost at the edge of the travelled surface of the road. The surface at the path gate was essentially level whereas the slope at the north edge of the sidewalk was 6.1%, as shown in the photos below.
The speed of pedestrians or cyclists crossing Gainsborough Road can be estimated from various research. However it is also helpful to obtain data from the actual site. The following table provides the time taken (in seconds) for cyclists and pedestrians to cross the 11.7 metres of pavement between the north and south curbs of Gainsborough.
A typical, 2-lane roadway might be about 8 metres wide. The extra road width at the site was due to the presence of a centre, mutual-turn lane as shown in the westward view below.
This westward view looking toward the path crossing shows a centre, left-turn lane that increased the curb-to-curb width of Gainsborough Road to 11.7 metres. This photo taken on September 13, 2020 also shows another (red) car parked at the west side of the path thus blocking visibility at the path.
While the average crossing time of the 23 observations in the above table was about 6.7 seconds there were a number of observations of much longer times. The previously mentioned 2 adults pushing the two toddlers on mini-cars (Observation #13) involved a crossing time of almost 14 seconds. An eastbound motor vehicle travelling at 80 km/h will travel about 22.2 metres per second. Thus in 14 seconds such a vehicle would travel about 311 metres. However, we must also remember that a crossing pedestrian would need additional time to survey the roadway, and then move forward to the curb before that 14 second count-down would begin. Thus one can see that the parents (?) in Observation 13 could be making a judgment to cross the road when a speeding vehicle could be well over 300 metres away, or even 400 metres away. In such long distances a pedestrian would not be capable of detecting the travel speed of a vehicle. For example it is well-established from past research that, barring additional ques, an observer would have difficulty detecting the speed of an approaching vehicle, using the expanding size of the vehicle in the observer’s field of view, until that vehicle is about 175 metres away. If there are sufficient numbers of cyclists and pedestrians who take such long times to cross this roadway then a reasonable solution is to install a signalized, pedestrian crossing at such a site.
The safety of the Gainsborough site is compromised by the lack of any signage warning drivers on Gainsborough Road of the presence of the multi-use (cycling) path. However signage is not always the best improvement as most drivers ignore their warnings.
Judging by the data collected on the Sunday afternoon of September 13, 2020, Gainsborough Road is well populated by motor vehicle traffic. The City of London indicates an Average Annual Daily Traffic (AADT) of 7500 vehicles for Gainsborough. Given what has been observed in our study and considering the rapid development in that edge of the City, it is likely that the present traffic volume is higher than what has been indicated in the City data. Residents who spoke with us during the video documentations advised that we should come to the site on a weekday afternoon peak-hour as the traffic volume would be much higher. This is a correct advisement as we were aware of that fact. The opportunities for users of the path to cross Gainsborough Road would likely be more limited on a weekday peak hour than what has been shown in our data.
The City of London is likely no different than many cities in Canada and North America where a rapid transformation is taking place from a transportation system designed for dominance by motor vehicles to one that includes active transportation. During this transition infrastructure modifications have involved compromises where certain developments are less than ideal from a safety viewpoint. While many new developments have the luxury of “starting from scratch” and thus including well-developed facilities for active transportation, older developments remain challenging. How do you insert a new, multi-use path system into an old traffic system that did not envisage such a need? At newer developments, how do you maintain safety until sufficient in-fill occurs and funds become available to complete certain safety projects that would otherwise remain incomplete? These are complicated and difficult decisions. Gorski Consulting continues to examine and report on cycling paths and facilities to illuminate where improvements need to be made.
Death of Cycling Professor – Part III – Further Results
This is the third article in a series of four, that discusses the findings of Gorski Consulting related to an examination of the site on Gainsborough Road in London, Ontario where a retired professor was killed when using a multi-use cycling path. The previous two articles provided results from the first 40 minutes of videotape of a two-hour session conducted on Sunday, September 13, 2020.
In the previous two articles the results of eastbound traffic volumes and speeds was provided for vehicles approaching the cycling path located on Gainsborough Road just west of Hyde Park Road on the western outskirts of London. It was apparent that a commercial event was taking place next to the site which caused large numbers of vehicles to enter and exit two driveways just west of the cycling path. It is likely that these turning vehicles caused interference to vehicles travelling straight through the site and therefore the speed of many vehicles was likely reduced.
The new data presented here is for an additional 40 minutes of observations. In the first 20 minutes of this new data there was a continuation of the disruptions caused by the turning vehicles. However in the second 20 minutes the commercial event must have come to an end as the number of turning vehicles ceased. This had an effect on the calculated speed of eastbound vehicles as indicated in the following tables.
The first table shows the average speed of all eastbound vehicles that travelled straight through the site. This table was shown in the previous article but now we have added the data from the “40 to 60 Minutes” and the “60 to 80 Minutes”. What this shows is a marked increase in average speeds as the number of observations decreased as the number of turning vehicles dropped in the “60 to 80 Minute” period.
This is indicated further when we look at the smaller number of observations containing only those vehicles that experienced no interference, shown in the table below.
With less interference the speed of eastbound vehicles increased such that between 200 and 100 metres west of the path the average speed of eastbound vehicles was in the range of 73 to 75 km/h. We can examine the data further by selecting just the speeding vehicles as shown in the following table.
Note in the table above that the number of speeding vehicles increased in the last 20 minutes (“60 to 80 minutes”). 70% of the eastbound vehicles were observed to be travelling at 72 km/h or higher. We even had two observations of vehicles travelling over 90 km/h. This is in an area where the maximum speed is posted at 60 km/h, reducing to 50 km/h just before reaching the cycling path.
Thus the data is beginning to show a trend whereby the average speed of vehicles appears to be unacceptably high when eastbound drivers are not interfered with their selected speed. We will have more to say once we complete the remaining 40 minutes of videotape and present the results in the final article on this issue.
Did A Young Mother Die In A Vehicle Fire? We Must Know
This is a very good photo of a London Police cruiser. But it has nothing to do with a vehicle fire that may have killed a young mother. That is a problem.
Everyone is devastated when a young life is lost due to the actions of an impaired driver. And we want to prevent its recurrence. Why does that same concern not apply to post collision fires?
News media reported that yesterday, October 3, 2020, a head-on collision occurred on Highbury Ave south of Manning Drive, on the southern edge of London, Ontario. At least one of the news outlets reported that a 35-year-old female was killed by the actions of an alcohol-impaired driver. Yet there was no mention of the fact that the woman died in a fire-engulfed vehicle.
A second news article posted by CTV News was more clear. It reported a post by Rebecca Blackmore who indicated “So many people, including her boyfriend, worked to try to pull the person out of the vehicle but couldn’t”.
In another post from Cindy Jones, she recalled “Yes, it was so horrible. My son is having a difficult time. He was trying to help getting her out. He said that the steering wheel and column was right against her. She said she couldn’t move (her) leg”.
CTV News reported that “Jones would like to see vehicles carry extinguishers”. Jones reportedly stated “I want to say something – everyone should buy a fire extinguishers for (their) vehicle. Could have made a difference. Her vehicle was pretty much gone by the time anyone showed up”.
CTV News also posted a statement by the deceased’s heartbroken husband.
There is no pleasure in reporting such facts. And many police and news refuse to do so. When a fire takes the life of someone the fact is hidden from the public as if this will somehow lighten the load for the family and friends of a deceased. But these short-sighted beliefs fail to address the very important fact that we need to make the public aware of these tragedies so they can be prevented. Hiding these outcomes does nothing to prevent them, it only enables them in the future.
Just two days ago Gorski Consulting posted an article on this website entitled “Silence About Post-Collision Fires”. There we wrote:
“The above incident reportedly occurred on September 30, 2020 at Perth County Road 135 and Line 44. OPP indicated that there were “No serious injuries”. However in many serious collisions doors can become jammed or occupants can become entrapped by deformation thus preventing escape from a post-collision vehicle. If a fire were to start, in many cases, the only hope is for emergency personnel to arrive in time to free an occupant. But if emergency personnel do not arrive in time, or if the extrication procedures become complicated, an occupant could be trapped without the possibility of escape. This is a real concern that cannot be avoided by silence. Steps must be taken to identify the numbers of post-collisions fires and why they seem to be occurring more often.”
What we wrote two days ago is precisely what occurred yesterday. A young mother did not escape a fire because she was trapped and no one could save her. What if we had posted this warning two years ago? (Actually we have posted man similar warnings in the past) What if police had made more effort to warn the public of these outcomes? What if police had informed the public that they were in contact with Transport Canada and that this federal agency was dealing with this potential safety problem? What if more news outlets such as CTV News in London took the courage to post these tragic results and get more public impetus for all responsible agencies to high-light this issue? Could we have saved this current tragedy from occurring? Unfortunately, in this instance, we will never know. But this is yet another opportunity to save the next future life by making all aware that vehicle occupants are dying in post-collision fires.
Silence About Post-Collision Fires
While the OPP are helpful in submitting basic photos of the collision sites they investigate, there is an apparent lack of information provided by all police forces regarding the large number of post-collision fires that are occurring in the region. In the example shown above the presence of the fire is obvious from the photo but there has been no acknowledgment of police that a fire could be very dangerous even after all safety devices have be successful in preventing a death or serious injury.
The above incident reportedly occurred on September 30, 2020 at Perth County Road 135 and Line 44. OPP indicated that there were “No serious injuries”. However in many serious collisions doors can become jammed or occupants can become entrapped by deformation thus preventing escape from a post-collision vehicle. If a fire were to start, in many cases, the only hope is for emergency personnel to arrive in time to free an occupant. But if emergency personnel do not arrive in time, or if the extrication procedures become complicated, an occupant could be trapped without the possibility of escape. This is a real concern that cannot be avoided by silence. Steps must be taken to identify the numbers of post-collisions fires and why they seem to be occurring more often.
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