Maintaining a Safe Following Distance

image of car in rear view showing poor following distanceI try very hard to maintain at least a two second following distance when I drive. This can sometimes be quite a challenge as it often seems that I am the only driver present that thinks this is a worthwhile accomplishment.

In fact, other drivers seem bent on preventing this because they seem quite happy filling up any available space and forcing me to constantly adjust my position.

Following Distance is a Space Margin

Beginning at page 72, the Learn to Drive Smart guide devotes some explanation to Space Margins. It explains the Two Second Rule and discusses braking distances.

It also sprinkles advice throughout chapter 6, Sharing the Road. It's a critical concept for new drivers to learn and accomplished drivers to retain and follow.

I've already mentioned maintaining my following distance but I also have to consider the distance from vehicles following me and minimizing the time that I spend beside other vehicles. Leaving yourself an "out" in case something happens is a never ending task.

Keeping Your Distance

Dealing with drivers in front of you is not that difficult. Simply slow slightly to create the necessary following distance again and then resume the speed of traffic. Yes, you may find yourself doing this continually, and it is annoying, but better safe than sorry!

The same method works for vehicles beside you. If they are not passing, adjust your position to be ahead or behind them and you have regained the desired space margin.


When someone seems bent on tailgating you, the situation can be more difficult. Some drivers will purposely attempt to bulldoze you out of the way so that they can do it again to the next vehicle in front of them.

On multi-lane road, it is often as simple as slowing slightly and letting the driver behind you decide to pass on their own.

Use the Right Lane

Of course, this assumes that you are in the right hand lane. If you aren't, you should be. Move over and let the driver by, even if you are doing the speed limit.

This becomes more difficult when there is only one lane of travel for each direction.

Slowing down when there is an opportunity for the vehicle behind to pass may work. If it doesn't, signal, pull over to the right and stop. Driving on the shoulder is illegal.

After the vehicle passes by, pull back onto the highway and continue on your way.

Use of Hazard Flashers

Turning on your hazard flashers or flashing your brake lights might not be a good idea. The driver behind may not be paying much attention and could decide to ignore the brake lights. This could lead to a collision.

Brake Checking

Whatever you do, don't decide to teach the other driver a lesson by stomping on your brakes! One bad behaviour does not justify another.

Leave More Space

In either case, it's time for you to leave more following distance in front because you are now making decisions for two drivers. More space means more time.

You can brake more slowly if something happens in front of you, giving the driver behind more time to react as well.

Traffic Tickets Issued

In 2022, 1,072 traffic tickets were written to drivers for following too closely. It appears to me that this behaviour is as common as speeding, yet in comparison, more than 194,674 speed related tickets were issued that year.

It would be interesting to know what portion of the 1,072 tickets were written in response to collisions and how many were the result of preventive enforcement.

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This video is good for one part which could reinforce mistaken beliefs some motorists have about where cyclist should be on the roadway.

At 05:28 the narrator refers to a cyclist "riding on the shoulder" but at 05:55 you can see that the cylist is not on the unpaved shoulder but is riding more or less along the white line at the edge of the paved lane. This is a dangerous position for two reasons:

- it's too easy for the cyclist to wander over the edge of the paved portion and lose control when trying to correct

- a position at the extreme edge of the lane will make to it more likely that overtaking motor vehicles will unsafely pass within the lane rather than waiting and passing when it's safe to encroach on the adjacent lane as he driver correctly did in the video.

Just saying.



... being as using the unpaved shoulder isn't a practicable option for a guy on a 10-speed road bike, the cyclist and the motorist were maximizing the available space for each other, which is really what the video is about.

Even though the video is probably 30+ years old, the principles of driving with maximum space and visibility don't ever change.

This is a great column on a very thorny subject. Everyone loves to moan about how impossible a 2 second tailback distance is, but the fact remains that the gas pedal works both ways, and momentary speed corrections to re-create your space margins actually generate virtually zero increase in trip time, but a huge and very significant increase in both safety and peace of mind.

What we know, however, is that regardless of the very well established knowledge on the point, no driver population around the world maintains a 2 second margin on average. Australian research found a range of .5 second to 1.7 seconds. The further question then is why we aren't crashing into each other in much larger numbers than we are, and the answer to that lies in the second "Key Defence" (to quote the Canada Safety Council) - Eye Lead Time. Effective attending and adequate forward vision are the critical variables keeping people out of each other's trunks, to the extent that they're in play. And we know from the Naturalistic Driving Studies that they're actually not in play to the extent we'd prefer, so the take-away from the research is plainly that an astonishing amount of the successful driving out there is down to the simple good fortune built in to multivariate systems.

This is where the pragmatism of Vision Zero offers tremendous potential  - recognizing that people do, and always will, screw up as we drive, we need to ensure that the traffic system has adequate fail-safes built into it. So, for instance, the absolutely critical point that vehicle speeds should be regulated to reflect relative potential injury severities in each scenario, rather than the simple speed habits of average drivers. As well, the emphasis on increasing the safety capabilities of vehicles, with systems like forward crash prevention, is again built on the understanding that there is a need for the vehicle to fill in the performance gaps of it's driver:  "the sensors are always on, monitoring the environment, even when the driver isn't".

Increasingly, we are seeing technology fill in the gaps in human performance, with commensurate reductions in carnage. But recent upward trends across North America in crash and injury rates are telling us that we can't afford to allow vehicle technology alone to solve the problem  - there is a pressing need to address the issue of de-regulation of the traffic environment,  and dis-regulation of driver behaviour. The speed limit increases that have been the trend over the past several years have had the obvious and predicted results: commensurate increases in crash frequencies and injury severities. Speed limits will need to be reduced, and those reduced limits considerably more enforced, if we are to reap the benefits of other safety measures.

This brings us on to the problem at the end of the article  - few tickets for space margin violations, relative to speeding tickets. Fact is, vehicles on average are consistently moving at roughly 10kms/hr over the speed limit, which we know generates a crash risk approximately equal to driving while .08 impaired. This means that dirvers are both more likely to crash, and also that the crash will entail more serious injuries. But, there simply cannot be enough enforcement of either speed or space margins while we rely only on police officers in police vehicles.

This is where technology has massive untapped potential in our province  - automated enforcement, anathema though it is to many, is nonetheless the obvious way forward, as proven in jurisdictions around the world that are posting dramatically lower rates of serious injury and fatality than we are. What can and should be rcognized is that systems like red light cameras are both significantly reducing the health care budget demands imposed by traffic collisions, and also capable of so much more. A single camera can accomplish red light monitoring, license plate monitoring re: stolen vehicles, driver behaviour monitoring re: distraction, and vehicle spacing and overspeed infractions, to name the most obvious few. A substantial increase in our use of available technology for vehicle/driver monitoring absolutely will reduce the carnage on our roads, if we will but acknowledge that lives saved is the goal, not lives wasted on "freedoms" to do whatever we bloody please behind the wheel. 

So  - safe margins, an essential goal. A goal that can, is, and will be better achieved by driver assistance technologies than by simply excoriating the legions of "tailgaters" out there. But still, only actually "safe" within the context of a safer traffic system that includes safer speeds actually commensurate with relative hazard of the road environments, and considerably more (and inevitably automated) enforcement of safety regulations. 

Thanks for the column - this was fun!




always a problem, I try to maintain it but other people don't want you to. I have a 36 foot motorhome and it becomes more of an issue. i try to maintain 5 seconds while travelling in it. Once again it becomes a problem especially in freeway travel. 

The 401 in the Toronto area was an issue this summer but the freeways in Quebec were the worst. I just keep adjusting because most drivers are either tailgaters or wish to cut you off as soon as they get by.

So the question is why do people tail gate for an extended period then pass and the cut back in and then slow down so once again I have to slow down. Sheesh makes me crazy. There must be a need for a study on this behaviour.