Lessons From An UnSafe Police Traffic Stop

Police have an obligation toward their safety, and drivers around them, to take note of how they perform traffic stops on high speed expressways. In an earlier article posted to this website on February 20, 2019 we reported on a proper and safe positioning at a police traffic stop. In the present article we present a situation where the traffic stop is not safe.

The current incident occurred on February 28, 2019, in the southbound lanes of Highbury Ave approaching the Commissioners Road overpass in London, Ontario. The photo below shows the southward approach to the area with the Commissioners Road overpass shown in the  background.

The important consideration in this incident is that the roadway contains a curve which makes if difficult for drivers, looking from a distance, to detect what lane vehicles are in. Also, police traffic stops normally occur such that the stopped vehicle and police vehicle are positioned on the right side of the road, not the left. The result is that, when drivers detect the emergency lights of a police vehicle their understanding of the Ontario Move Over Law instinctively causes them to believe they will need to move over to the left.

As can be seen in the above photo, as well as the one below, a passenger car is situated in the left lane and a straight truck is situated in the right lane and they are travelling essentially side-by-side. The car’s position may have been influenced by the fact that, a few seconds earlier, the driver did not correctly detect the position of the police cruiser and made the inference that he/she had to be in the left lane to bypass the traffic stop.

The situation is not as dire because there is plenty of visibility ahead and the passenger car driver could brake if a safe change of lanes was not possible. But that will not always be the case. In many instances tall and and long tractor-trailers travel these expressways and on some occasions they may inhabit the left lane, thus blocking the view of drivers behind them. Thus if we use our imaginations and place such a large transport truck in the left lane, in front of the passenger car, we can see the danger that would be created. It would not be helpful that the passenger car driver may have detected the emergency lights from a long distance when the position of the police vehicle could not be determined. The view obstruction caused by the imagined large truck would prevent the passenger car driver of recognizing that the police cruiser was in the left lane a short distance ahead. If the imagined truck driver then steered into the right lane it would expose the position of the stopped police vehicle but often too late to prevent an emergency situation.  The passenger car driver could have little time to react.

Even if such an imagined large truck was not present, the photo below shows that even passenger cars  can create view obstructions at critical times. In the photo below the police vehicle’s emergency lights are barely visible over top of the passenger car roof.

As shown in the photo below, the passenger car that was in the left lane was able to complete the lane change into the right lane but that lane change was rather late. In the photo below the car’s left tires are still substantially in the left lane even though it is relatively close to the stopped police vehicle. Had there been a greater viewing obstruction or some form of distraction one can see that the danger of striking the police vehicle is a real possibility.

The photo below shows the position of the police vehicle and a small portion of the stopped vehicle. The stopped vehicle appears to be located completely off the paved road surface whereas the police vehicle is stopped substantially in the passing lane of the expressway. There are reasons why such a staggered position may be appropriate. For one thing, it can protect the police officer if he has to stand on the right side of the stopped vehicle to discuss matters with the stopped driver.

Indeed that is what has happened in the present case, as can be seen in the photo below. By placing the police vehicle in the offset position the officer believes that he will be protected from impact. However this positioning cannot be done in the absence of proper training that can inform the officer about the critical factors involved and what probabilities are associated with certain decisions.

In the present case the police officer needs to consider how far he needs to place his vehicle behind the stopped vehicle. If an impact were to take place to the rear of that police vehicle the officer needs to have some appreciation of how that vehicle will be pushed forward, at what angle, what rotation and what post-impact speed.

A central impact to the full rear will increase the post-impact velocity of the police vehicle and will make it travel in a relatively straight line and produce less rotation. An impact that is offset to the right of the police vehicle’s rear end will reduce the vehicle’s post-impact speed, cause more rotation and will likely  induce a greater curved travel path. But these differences in motion will develop over certain distances so one needs to consider what distances are being discussed. If the police vehicle is stopped a very short distance from the rear of the stopped vehicle then the relevant post-impact motions will be different than if the police vehicle is positioned 20 metres away.

At highway speeds of 100 km/h, or about 28 metres per second, a vehicle applying emergency braking on a good and dry surface might reduce its speed at a rate of about 6.9 metres per second every second. Thus in two seconds the speed of  such a braking vehicle would lose about 14 of the original 28 metres per second. Converting to km/h, the striking vehicle would still be travelling at about 50 km/h when it impacted the police vehicle. Assuming that both vehicles were of an approximate similar mass, and assuming that all four wheels of the struck police vehicle were fully locked during post-impact sliding, the police vehicle might be pushed forward at a speed of about 25 km/h and substantial speed would be lost during post-impact sliding such that the sliding police vehicle might be travelling at less than 25 km/h should it strike the officer. However, if the officer had placed his vehicle with less offset to the stopped vehicle there would be a greater chance that the struck police vehicle would impact the stopped vehicle ahead of it and therefore this would contribute to a further reduction the police vehicle’s post-impact speed. The intention is to use the mass of both stopped vehicles as barriers that protect the officer. But all these matters are hypothetical. If the striking vehicle is a large truck the situation becomes much more grave.

In the present scenario the police officer needed to stop his/her vehicle with much less offset from the stopped vehicle and with a  larger gap in distance between the two vehicles. A lessened offset would still protect the officer from an impact by a stray vehicle. This is so because, the higher the speed of an approaching vehicle the less opportunity it has to change its lateral position in a given distance.  So the officer needs to take into account the expected travel speed of vehicles on the highway and then adjusted his stopped position based on that factor. If the officer had been properly trained about how loss-of-control vehicles change their lateral position he/she might select a safety position of the police vehicle for any given roadway scenario.

As the stopped vehicle was fully off the paved road surface the police officer should also have brought his/her vehicle to a stop off the paved surface. As typical highway lanes may be 3.5 to 40 metres wide, and a typical SUV might be 1.8 to 2.0 metres wide, there is leeway to allow a stopped position that encroaches into a driving lane while also allowing vehicles to pass by. So a position where the right side of the police vehicle is at the painted edge-line of the lane still gives most vehicles the ability to pass the stopped police vehicle. Obviously with larger vehicles such as tractor-trailers, which might be 2.6 metres in width, the situation is less safe.

There will be situations where police have no choice but to stop in the position shown this scenario. If the stopped vehicle was disabled and could not be moved then that would be situation where the police officer might use the police vehicle to draw attention to the stopped vehicle. And generally, there are situations where traffic stops cannot occur to the right of the highway. This poses a problem. A good habit is to set up pylons (traffic cones) on the lane as quickly as possible to direct traffic away from the stopped police vehicle. It needs to be stressed that the illumination of any emergency or special lighting on any vehicle is not sufficient to inform drivers that the vehicle is stopped. Those lights are only there to draw attention to the vehicle. Traffic cones give the additional information to drivers that the lane ahead is closed. It is also important to place traffic cones much further away from stopped vehicles than most persons realize. Therefore it would not be an unreasonable action for police to take a few moments to place traffic cones behind their stopped position as a way to provide further guidance to approaching drivers.

Overall a police traffic stop on an expressway should be avoided where possible. It is a dangerous situation that often leads to deadly consequences. On its own it is dangerous for an officer to approach unknown persons in an unknown vehicle let alone consider the dangers of being struck by passing traffic. If a traffic stop cannot be avoided police need to do their best to place stopped vehicles to the right side of the road as far as possible. Police should never become over confident that their emergency lighting will be good enough to warn drivers of their presence and location. There are many dangerous scenarios that can develop which are difficult to foresee.