September is reported to be “National Manners Month”—a good time to look at one of the most important ‘courtesy’ road rules. People driving more slowly in the passing lanes than the cars coming up behind them cause a hazard by impeding the free flow of traffic even if they are driving close to the posted speed limit.
Failing to keep right to allow faster moving vehicles to pass in the left lane causes traffic congestion, is unsafe and may be discourteous. The rule applies whether or not it is expressly posted. It does not excuse the discourtesy of the overly aggressive and perhaps excessively speeding left-lane driver who communicates a wish to pass by tailgating, honking, light flashing or other aggressive behaviour. Safe drivers, however, drive with their heads and try to keep their emotions under check.
Safe multi-lane driving requires focus, attention, and skill. In ideal conditions, on average, traffic moves at or close to the posted speed limit. ‘On average’ means vehicle speeds will vary. Exceeding the limit —excessively over or under—may be a ticketable offence. Some vehicles may be limited by law to the right lane or will choose to limit themselves to right lane travel. Drivers who drive at or slightly under the speed limit in the right lane will need to, should use, and should be permitted to use the passing lanes when they encounter slower moving vehicles in the right lanes.
Proper use of the passing lanes helps minimize traffic congestion. Imagine a slow green car passing (in the left lane) an even slower blue car (in the right lane). A red car behind the green car wants to go faster (hopefully, all within the speed limit). To do so either the green car or the red car has to move into the right lane. Because it is ahead, the green car can move into the right lane sooner, (or more efficiently) than the red car. If the green car moves into the right lane, this allows the red car to resume its former speed sooner than if the green car stays in the left lane forcing the red car to move to the right lane, and back to the left (passing) lane.
It may not seem like much but the green car, by moving out of the left lane to let the red car pass, enables the red car to spend less time on the highway—maybe just seconds less, but, as someone said in relation to traffic flow, “milliseconds add up to gridlock.”
Some other things to bear in mind: Drivers who prefer the right lane may not be as skilled at changing lanes as they should be. Expect right lane traffic to move into the left lane at any moment. Passing any vehicle requires a watchful eye. Passing another vehicle never creates freedom to exceed the speed limit. And, using the right lane to pass is unconventional, unexpected, and may be illegal.