Recent multi-vehicle pile-ups on Highway 400 and 401 in southern Ontario demonstrate the challenges that exist when road surface and weather conditions deteriorate. The extent of those problems is rarely publicized as government agencies that are responsible for roadway maintenance and control risk being criticized for the existence of those conditions. The propaganda of blaming drivers is tied to the conflict of interest of being sued for the existence of substandard road conditions.
Ontario’s Minimum Maintenance Standards (MMS) for roadways were enacted principally by the defendants in potential civil litigation. The MMS generally state that actions to improve the surface conditions of a road do not have to begin until several inches/centimetres of snow have accumulated on that surface. In practice this means that, by the time plows or sanders are sent out, there will likely have been several hours of dangerous conditions existing on most roadways. This in the time when drivers are caught by surprise as surface conditions deteriorate unexpectedly.
There may be many combinations of ice, snow and bare pavement on any roadway at any particular time. The traction provided by these conditions can vary greatly. Given a bare pavement a driver applying maximum braking from an initial speed of 80 km/h could bring a typical passenger car to stop in about 36 metres or less. The same vehicle being braked on snow could stop in about 100 metres. And the same vehicle braked on ice would require over 500 metres to stop. These values are based on estimated coefficient-of-friction values of 0.7, 0.25 and 0.05 respectively. The lower the coefficient of friction the less traction is provided. These differences are very large. However, not all surfaces are fully bare, snow-covered or ice-covered. Often surfaces contain a mixture of all three conditions.
The road surface in this photo obviously contains snow but do the dark areas contain bare pavement or are they icy? While travelling at highway speed it is not easy to be sure as the surface may appear blurry.
So a road surface that is predominantly bare may contain patches of snow or ice. But how would a driver be able to tell what level of traction the surface might provide? A braking test could be done but not in the middle of a busy expressway. A reasonable estimate for such road surface might be in the range of 0.6 and result in a braking distance of 44 metres from an initial speed of 80 km/h. But a slight difference in composition of snow and ice might bring the coefficient-of-friction down to 0.4, with a resultant braking distance of about 63 metres. That is a difference in braking distance of almost 20 metres. Converted into the scenario of a bare road surface a braking distance difference of 20 metres would be the difference between travelling 80 km/h and 99 km/h.
And what if we have even worse road surface conditions? What if a driver is travelling along a highway in rain and the temperature is steadily dropping from just above freezing to below freezing. With steady high-speed traffic the wheel track areas of the surface might remain wet due to the heat caused by friction between the tires and the surface. But just outside of those wheel tracks, where there is no such heating taking place, the road surface begins to turn to ice. A driver looking at the reflections coming from a wet road surface has difficulty detecting that a similar level of reflection takes place from an icy road surface. A wet road surface might possess a coefficient-of-friction of about 0.5 but the icy surface might contain levels of 0.1 or 0.05. What would happen if the driver needed to change the vehicle’s lateral position in the lane due to some form of traffic disturbance ahead? At 80 km/h the vehicle travelling on the wet surface would be braked to a stop in about 50 metres, whereas we already indicated earlier that the same braking action could lead to a braking distance of over 500 metres.
A reflection of the red traffic signal on the pavement in this photo shows that the roadway may be wet or icy. That distinction can be difficult to make. Yet failure in a correct identification could lead to dire consequences.
The point of this discussion is to demonstrate that driving in winter where rain or snow may be falling, and where there are combinations of wet, snowy and icy conditions results in a challenging safety environment. There will always be the segment of drivers who are reckless and inattentive thus causing collisions regardless of the weather conditions. But there will also be a segment who are driving in a reasonable manner but whose expectations are violated through no fault of their own. This is not only because the traction conditions of a road surface are difficult to read but also because those conditions change. That change may not only be related to changing weather. Changes may occur due to plowing and sanding actions that are terminated, disrupted or occur only on partial areas of a highway.
In this example, road salt has been applied in the vicinity of an intersection on the basis that such maintenance is of a higher priority at such locations. However the termination of that maintenance beyond the intersection means that the road surface could change from being wet to icy without warning.
While in many instances plowing, salting and sanding actions are deemed helpful, they also create differences in road surface conditions in areas where those actions are terminated or are incomplete. A road segment that receives a fresh coating of salt may seem safe to travel at higher speed. Yet, when that salting is terminated at an unexpected location a road surface may become icy without any prior warning. Similarly plowing actions that are terminated or are incomplete result in unexpected changes to road surface conditions.
In this example, plows have cleared this section of Highway 401 but have failed to clear the snow on the exit ramp. Such changes in surface condition can be unexpected.
Those who are responsible for the maintenance of roadways are often in a conflict of interest. Those who are direct employees of a municipality, or the Ontario government, are not free to discuss the problems that may exist because this could lead to claims from civil litigation against their employers. Similarly, those contracted to do maintenance work for municipalities and the Provincial government may be held liable if problems are revealed with road conditions that they are responsible to correct. Even police share that conflict of interest as they receive their marching orders down from a chain of command that, at its peak, is operated by the government that could be held liable for road safety problems. The primary purpose of many official agencies becomes a case of deflecting responsibility for road safety problems rather than correcting them.
In this milieu of complicated road surface changes, vast differences in driving habits, vested interests, and confusing propaganda the target of improving public safety continues to shift in the winds with striking a bull’s eye being more a matter of luck rather than well-planned intellectual strategy.
You must be logged in to post a comment.