Highway median cross over collisions can be deadly. Therefore it is good news that a transport truck was kept within the median of Highway 401 rather than crossing into opposing lanes near Kenesserie Road on Saturday, August 18th, 2018. But the issue is more complicated than that.
The OPP reported that at about 0030 hours on Saturday an eastbound pick-up truck was hauling an engine on a flatbed trailer when its driver lost control due to the wet road conditions. The pick-up struck the newly installed high tension median barrier causing the engine to become dislodged and it flew into the opposing, westbound lanes of the highway. A westbound transport truck struck the engine and went out of control, driving into the median where it struck the cable barrier preventing the truck from travelling into the opposing eastbound lanes. This was hailed by the OPP as a success story in that there were no injuries and therefore the median barrier successfully prevented a deadly median barrier cross-over collision. Well, yes, it prevented the vehicles from crossing the median, but the celebration fails to recognize the important fact that the engine was not prevented from crossing the median, and that is a problem.
There was no description of the engine involved but it could easily have weighed a 1000 pounds. Even much less massive objects flying into opposing lanes can be deadly. What if the engine had struck a smaller vehicle such as a car or a light duty truck? Would the consequences have been just a favourable? Clearly not.
While there appear to have been some benefits to the presence of the newly-installed cable barrier, this incident does not prove that it was the right choice for installation over the more costly concrete barrier. What is needed is more information and experience from further incidents before any conclusions can be drawn. The problem is that the details of what transpires during these incidents are not provided for the public to evaluate. Nor is it likely that any such details will ever be provided. And that is another problem.
The OPP uploaded several photos of two vehicles involved in a fatal collision on Hwy 48 north-east of Toronto over the weekend. The photo above shows the two involved vehicles. A 25-year-old female occupant of one of the vehicles reportedly sustained fatal injuries. While the reasons why occupants do not survive such impacts may be complicated by unreported facts, the public should become critical observers of incidents like these that do not provide an obvious reason for the fatal consequence.
The safety of modern, light-duty vehicles has improved greatly over the decades such that the collisions that were deemed not survivable only 40 years ago are certainly survivable today. This is particularly true of frontal impacts of two vehicles approaching from opposite directions such as the one shown in the photo above. A distance approaching 1.5 metres from the front end of such a typical vehicle to the location of an occupied front seat is the key factor enabling the controlled ride-down of the occupants. A wide variety of safety systems can be deployed in the 1/10th of a second of such a crash that were not present 40 years ago.
In those earlier years most persons did not wear seatbelts and even if these restraints were worn they were of poor design. Similarly the frontal structures of those older vehicles did not crush in a controlled manner such that in many instances the structure of the crushed vehicle would penetrate into the occupant’s space. Air bags were also not available but even the early air bag systems were too aggressive and caused their own safety problems. Although some challenges remain, for the most part air bag systems have improved while being incorporated into the full system of other safety devices.
While it is not apparent to the general public, a key ingredient in the improved safety of head-on crashes was the implementation of “pre-tensioners” in restraint systems. In earlier days seat belt loading marks were measured by investigators to determine how they were being used at the time of an impact. That data showed that the loading did not occur until the occupant was in a “full-forward” position, similar to the position if the occupant had placed their seat in a full forward position on the seat’s adjustment track. Clearly this was not a recipe for improving the safety of occupants because the restraining was occurring too late in the crash. There are many reasons why this is not a good idea but this will not be discussed here. The point is that pre-tensioners are fired in the same manner as an air bag causing about 4 inches (10 centimetres) of webbing to be pulled toward the occupant’s body. This is a tremendous improvement in the commencement of ride down at an early stage resulting in tremendous improvement in occupant safety.
In summary the photo above shows a classic case where the frontal structures of both vehicles appear to have performed well. Although there is a lot of crush this is a good result. Crush is needed to dissipate the kinetic energy possessed by both vehicles prior to impact. The full frontal engagement of both vehicles is somewhat uncommon but it suggests that most of the kinetic energy would have been dissipated by the vehicles and that the impact force was relatively close to the centre-of-gravity of each vehicle. While this is not ideal it also allows the full frontal mass of the vehicles to be involved in the dissipation. Most head-on collisions involve in the range of a 50 percent overlap and therefore half a vehicle’s frontal structure is not helping in the controlled ride-down. So there are trade-offs.
A good crush is demonstrated by the lack of rearward displacement of the A-pillars of each vehicle. The A-pillars are those that are located on each side of the windshield. Where there is rearward displacement of such pillars there is often a compromising of the near-occupant’s seating space and this is a bad result. So seeing the lack of any A-pillar displacement is a good sign.
Also, while there appears to be substantial crush it is not overwhelming. Examining the position of the front wheels In the wheel-wells is also a general indicator of the extent of maximum crush as well as the degree of crush of the front edges of the hood of each vehicle. All these facts point to a collision severity that was manageable.
So these facts lead to the expectation that the occupants of each vehicle should have survived the crash. So why did a 25-year-old female sustain fatal injuries in this crash? This question should not be left unanswered. While there may be reasons that have not been explained or revealed, the public should be prepared to recognize when something is not quite right in the reporting of such tragedies.
Gorski Consulting is conducting a variety of testing involving bicycling on vertical alignments on roadways and bicycling paths. Testing is being prepared along a new section of a bicycling path completed in the summer of 2018 in east London, as shown in the above graphic of London, Ontario.
The graphic below shows the general alignment of the new path which is approximately 1 kilometer long and extends southward from Trafalgar Road in Kiwanis Park.
The graphic below is a Google Maps image looking south from the bridge at Trafalgar Road that crosses Pottersburg Creek. This view was taken in July, 2016, before the construction of the path was begun.
It has been observed that steep vertical alignments of roadways and bicycling paths pose a challenge to cyclists. Data is needed to examine how cyclists travel up and down such alignments and what safety hazards may develop. In preparation for this study the 1 kilometer section of the new path has been marked at 25 metre intervals, north and south of the Canadian National Railway bridge which is approximately in the middle of the new path. This new bridge was chosen as the starting point of testing because of its high altitude. Riders would be descending from the bridge whether travelling north or south.
The photo below shows a view of the CN railway bridge looking south. A typical marker showing “25” metres is with reference to the north end of the bridge.
The photo below shows the bridge from the south side, looking north, or opposite to the view shown above.
View looking north from 25 metres south of the CN railway bridge.The photo below shows the section of the bicycle path from 25 metres south of the CN railway bridge. The downgrade along with a sweeping left curve provide some challenging conditions where cycling speeds are likely to be elevated.
The photo below shows a view looking south from 75 metres north of the CN railway bridge. Again riders experience a significant downgrade while traveling toward the camera and this will create significant speeds of bicyclists.
A particular concern and interest relates to the conditions of the new path as cyclists travel northward from the CN railway bridge and toward the underpass at Trafalgar Road.
The photo below shows the downgrade of the path at 75 metres north of the railway bridge. The path meanders in the background and reaches the Trafalgar Road underpass at approximately 300 metres north of the CN railway bridge.
Elevated speeds of bicyclists are expected as they continue to travel northward along the downgrade. As shown in the photo below the path levels off near the 200 metre location north of the CN bridge and then it makes a right turn to travel toward the Trafalgar Road underpass in the background. Even though there is a leveling off of the downgrade it is expected that cyclists will still be travelling at an elevated speed in this zone.
As shown below, the path makes a right turn toward a bridge that crosses Pottersburg Creek just before making a dramatic left turn to go into the underpass of Trafalgar Road. The downslope is increased slightly in the vicinity of the bridge and this should make the left turn challenging at the expected higher cyclist speeds.
The photo below shows how the path comes to a “T” terminal point and riders must turn sharply to the left to go down into the Trafalgar Road underpass.
The change in direction of the path for northbound cyclists into the underpass is challenging due to the downgrade along with other factors. The photo below shows some of the problems. The line of sight to travel into the underpass is very limited.
View looking north at the Trafalgar underpass.The photo below shows the extent of the downgrade, curvature and the lack of sight lines for northbound cyclists travelling toward the camera. Persons walking within the underpass will not be seen and corrections by northbound cyclists could direct them into the railing at elevated speed.
The photo below provides an overall view of the bike path as it approaches Trafalgar Road and the “T” terminal of the path.
View looking south from the Trafalgar Road bridge showing the bridge crossing Pottersburg Creek and the “T” terminal point where northbound cyclists must make a sharp left turn to go into the underpass.
These photos provide some of the reasons why Gorski Consulting has chosen this site to conduct the bicycling testing which we hope will be discussed in further news items and articles on the Gorski Consulting website.
A well-meaning decision to re-align the difficult curves of “Snake Hill” along the west portion of Commissioners Road in London, Ontario may lead to dangerous conditions for cyclists riding on the steep downgrade that City staff and politicians may have under-estimated. The decision to make the re-alignment will not cause actual work to begin until 15 to 20 years in the future so there should be some leeway to consider what problems may be created.
While the actual re-alignment of the road is a separate matter, City staff and politicians appear to have agreed that, once the road is re-aligned the original road will remain to be turned into a multi-use path for cyclists and pedestrians. And this is the main concern: the safety of the cyclists.
The London Free Press quoted several residents in their article on the proposed changes. The general consensus is that the 11.8 percent slope of the hill is a safety problem and the realignment will improve the slope making it more gradual. Many vehicles such as transit buses, truck and emergency vehicles have been prevented from using the curve because of the safety concerns. And cyclists must avoid the curve for similar reasons. So everyone is quoted as being happy with the progress of improving the curve.
What has not been discussed is what will happen when the original and dangerous roadway is turned into a pathway for exclusive use by cyclists and pedestrians. While the average slope was estimated at 11.8 percent, there are undoubtedly smaller segments that are steeper than that average. The slope was deemed to be a safety hazard for motorized vehicles even though drivers of such vehicles can place their transmissions into a lower gear and thus neutralize the effects of gravity to some degree.
But bicycles do not have a lower gear on downslopes. The gears that bikes have change the effort required to pedal up slopes, not down slopes. Other than braking there is nothing that a cyclist can do to prevent gravity from increasing the speed of a cycle. As an example, recent bicycle testing conducted on a less steep hill in London (Meadowlily Road in east London) showed that at an average downslope of just 6.5 percent a cycle, commencing from a stopped position, would cause a bicycle to reach speeds in the order of 45 km/h in 400 metres from coasting alone. What speed could be attained if a cyclist approached the Snake Hill curve at a typical speed of 18 to 20 km/h and then performed a small amount of pedaling before recognizing the extent of the slope?
The problem for cyclists is exacerbated because a cycle is very dependent on the conditions of the surface on which it travels to maintain control of the cycle. And this is crucial on a steep downslope that might be misjudged. Road surface conditions such as water, dirt or sand or any degree of roughness or patching of the pavement could mean that a cyclist could be destabilized. Also braking would be compromised because there is a danger in braking a cycling while travelling over such surface conditions that is not shared by a 4-wheeled motor vehicle.
So if the slopes of Snake Hill were dangerous to the motor vehicle driving public, why is it OK to cause cyclists to use it when they are in even greater danger than motor vehicle drivers? Hopefully someone will think about his before many meaningful shovels are but in the earth.
There are not very many success stories being observed when it comes to vehicle impacts with guardrail terminals. Yesterday the Ontario Provincial Police uploaded a photo on their twitter account showing a potentially successful impact. The problem is, the driver still sustained serious injuries.
What is visible in the OPP photo is that the barrier bar has been split into individual sections and these sections have deformed into individual, curled ribbons. This is the type of deformation that causes the kinetic energy of an impacting vehicle to be dissipated in a controlled manner. Although there is damage to the front end of the vehicle that damage is moderate as exemplified by the lack of crush to the hood, no significant deformation around the left front wheel well, and the A-pillars are in their pre-crash state. So both the exterior of the vehicle and the barrier would appear to have done their job in working together to dissipate energy in a controlled manner. Such a combined dissipation means that the vehicle decelerates over a longer time and distance and therefore there is greater opportunity for the safety systems in the vehicle interior to perform in further reducing the severity of the forces exerted on the driver’s body.
So there is a little bit of mystery as to why the 81-year-old female driver of this vehicle sustained serious injury. It is not unusual to note that as persons age they are more frail and are prong to higher severities of injury than a younger person. But even so the severity of the forces that should have been exerted in this crash would be quite low provided that the interactions with the seat-belt and air bag systems were as expected.
This is another example where further probing is needed to determine what the specific injuries were and if they are the type that can be deemed acceptable. As an example, rib fractures might take place which are adjacent to each other and, because there is more than one fracture it ups the severity level of injury according to scales such as the Abbreviated Injury Scale (AIS). Yet if the driver had weak bones due to arthritis those injuries might be deemed understandable if they are not comminuted or displaced.
It is explanations such as these that can inform the public of the status of the safety systems around them and whether they are performing properly.