It may be thought that the risks involved in “going with the flow” of traffic, which you are doing when you drive on a laned roadway, are much less than the risks involved in dealing with oncoming traffic, for example, when turning left. Left-turn collisions and other types of head-on collisions of course often result in fatalities. But unsafe lane changes also cause a lot of accidents and injuries. For instance, on highways, from time to time unsafe lane changes cause multi-car pile-ups. With the speeds involved, the injuries are often very serious.
Although Vancouver is not an expressway city like Los Angeles or even Toronto, a lot of the Lower Mainland driving is on roads with two or three lanes in both directions. Section 151 of the Motor Vehicle Act requires that a driver who is driving a vehicle on a laned roadway “must not drive it from one lane to another unless the driver has ascertained that movement can be made with safety and will in no way affect the travel of another vehicle.”
While the general rule is that when one vehicle hits another from behind, the driver of the striking vehicle is to blame, that presumption may be displaced, and the situation where it is most likely not to apply is when the “vehicle in front” has made an unsafe lane change, and the driver of the striking vehicle has no opportunity to avoid a crash.
Please note that the unsafe lane change scenario is very different from the situation where the vehicle in front for unusual reasons unexpectedly slows down or stops. A sudden decrease in speed on the part of the lead vehicle generally will be one of the contingencies that should be anticipated by the driver of the following vehicle.
Slow moving traffic may in some circumstances, usually in a highway setting, be obliged to change lanes into the “slow lane”. If a traffic control device directs slow-moving traffic to use a designated lane, the slow-moving traffic must safely move over, (usually to the right).
It is also important to remember that the burden to yield the right of way falls on the driver attempting to get into the laned roadway from a roadside parking spot. When a vehicle moves into a lane from curbside parking, a vehicle established in the lane has the right-of-way and the driver leaving the parking spot has to be patient and careful. A lot of accidents result from vehicles leaving parking spots and cutting off approaching vehicles.
Good timing is the key to successfully moving from lane to lane. Good timing involves watchfulness and anticipating what the drivers around you are doing, and it involves letting these drivers know your intentions. Good timing cannot be achieved unless speed is moderated. Too much speed means too little control, no time to correct for one’s own mistakes, and no time to adjust to the mistakes of others. Please drive safely.
Road Rules by Cedric Hughes and Leslie McGuffin