Lanes, passing and merging

Reading the lines and choosing a lane

Road markings are instructions. A broken line may be crossed when it is safe. A solid line beside you means stay where you are. A double solid line between opposing traffic means neither direction may cross to pass. Where you see one solid and one broken line together, the rule applies to the side you are on: broken on your side means you may pass, solid on your side means you may not, even though the driver coming the other way is allowed to.

Lane choice on a multi lane road follows one simple habit: keep right except to pass. The left lane is for passing and for turning left, and sitting in it at the same speed as the traffic beside you creates the frustration that produces risky passes further back. Where lanes are marked with arrows, the arrows govern, so read them early and move across in good time.

Inside your own lane you have room to position yourself. Move a little away from a row of parked cars so an opening door cannot reach you, a little away from a cyclist while you pass, a little away from an oncoming truck on a narrow road, and out of the deep ruts and slush where the surface is worst. None of that requires leaving your lane. Small adjustments buy you room, and room buys you time.

Changing lanes without surprising anyone

A lane change has an order and the order is what makes it safe. Check your mirror to see the traffic behind, signal in time for other drivers to understand what you plan, check the mirror again, turn your head to look in the blind spot on the side you are moving toward, and only then move over smoothly and cancel the signal.

The head check is not optional and it is not a glance in the mirror. Every car has areas along its rear quarters that no mirror covers, and a whole motorcycle or a small car can sit in one of them. Mirrors set wide, so that you see slightly beyond the side of your own car rather than the side of your own car, shrink those areas but never remove them.

Signal early enough to be useful, but treat your own signal as information rather than permission. Other drivers do not always give way, and a signal does not create a space. Make the move only once you can see the space is there, and never change more than one lane at a time, because a driver two lanes over cannot follow what you are doing.

Passing on a two way road

Passing on an ordinary two way road is the most demanding thing an average driver does, because it puts you in the path of oncoming traffic on purpose. Before you commit, four things must be true: the line on your side allows it, no sign forbids it, you can see far enough ahead to complete the pass and return with room to spare, and there is nothing about the situation ahead, such as a crest, a curve, an intersection or a crossing, that could hide a vehicle from you.

You pass on the left as a rule. Passing on the right is allowed only in limited situations, such as a road with two or more lanes going your way, or where the vehicle ahead has moved left and signalled a left turn, and never by using the shoulder. Once you begin, use a firm and steady speed, keep the whole move short, and return to your lane only when you can see the vehicle you passed in your interior mirror.

Judging oncoming closing speed is the part people get wrong, because two vehicles approaching each other close the gap far faster than either one is travelling. If there is any doubt, do not pass. Almost nothing is achieved by getting past one vehicle, and the road will offer a proper opportunity soon enough.

Merging and lanes that end

Joining a highway means using the ramp and the acceleration lane to get to the speed of the traffic already on the road, checking over your shoulder for a gap, and blending in. Stopping at the end of an acceleration lane is dangerous and is nearly always a mistake, because the traffic behind expects you to be moving and the gap you need is much larger from a standstill.

Drivers already on the highway have a part to play too. Where it is safe, ease off slightly or move over a lane to make room for a vehicle joining, rather than closing the gap. This costs almost nothing and prevents the sudden braking that ripples back through traffic.

When a lane ends, traffic in the ending lane merges into the lane that continues. The orderly version is to use the full length of the ending lane, then take turns one for one where the lanes meet. That is faster for everybody than merging early into a solid line of vehicles, and it is what the diagram shows. Signal, match speed, and slot in without forcing anyone to brake hard.

Around big vehicles and in bad places to pass

Passing a large truck or a bus takes longer than passing a car and puts you alongside a vehicle with much bigger blind areas. Do not sit beside one. Get past decisively, and do not cut back in until you can see its whole front in your interior mirror, because a loaded truck needs a long distance to stop and you have just taken part of it away.

Some places are simply the wrong ones to pass: approaching an intersection or a railway crossing, near a pedestrian crossing, on a bridge or in a tunnel where there is no room, in a school or playground zone, and anywhere a sign forbids it. Where a stopped school bus is showing red flashing lights, you do not pass at all. The details of some of these are provincial, so read the list in the guide for your own province.