Traffic Law
"No motor vehicle shall be driven on a highway at such a slow rate of speed as to impede or block the normal and reasonable movement of traffic thereon except when the slow rate of speed is necessary for safe operation having regard to all the circumstances."

Thus §132 of the Highway Traffic Act establishes the traffic law for the Canadian Province of Ontario, prohibiting slow driving.

Although not the killer speeding is, slow driving is responsible for a considerable degree of carnage on our roads.

One economist wrote in the American Economic Review:

"... all current safety campaigns emphasize that speed kills. They imply that the slower driver is the virtuous one and is helping protect himself and other drivers. It isn't so. To reduce fatalities, it is important that everyone drive at about the same speed. Thus the major consideration in choosing a speed limit is that it be obeyed. And the major consideration for police is to reduce variation, not speed, because slow drivers are as much a public hazard as fast ones."

The statutory form of prohibition as exhibited by the Ontario statute, is similar in most Canadian jurisdictions; for example, §145 of the Motor Vehicle Act of British Columbia, §144 of New Brunswick's Motor Vehicle Act or §33(3) of Saskatchewan's Highway Traffic Act. Rather than ban slow driving per se, some jurisdictions oblige their licensed motorists to maintain a reasonable speed.

However, some jurisdictions merely direct the slow moving vehicles to keep to the right or subject them to the discretion of a peace officer as to their redirection or removal from a highway. This article is concerned with those jurisdictions which have slow driving prohibitions or reasonable speed obligations.

The typical slow driving prohibition includes a safety-hatch for circumstances where, to defer to the words of the Ontario statute, the "slow rate of speed is necessary for safe operation having regard to all the circumstances."

TurtleIn R v Chamberlain, the driver (Robert Chamberlain) was having trouble with his door and had to slow down so he could use one hand to keep the van door closed, all the while tying up traffic on the heavily travelled two lane section of highway No. 1, near Sussex, New Brunswick.

As traffic lined up behind him and a few hardy souls inched out trying to pass him, the police (RCMP) pulled him over and charged him with slow driving. Robert Chamberlain tried to rely on the safety hatch in the slow driving prohibition. Indeed, it was true that his slow rate of speed was making the road safer for him ... but just him. For the rest of the users of Highway #1, Chamberlain's slow driving was making conditions dangerous.

He was convicted of the charge of failing to maintain reasonable speed.

The contrary result occurred in Mosely v Spray Lakes Sawmills, a case where the plaintiff alleged that the truck driver/defendant was negligent because he was driving too slow, contrary to the law. The truck driver was hit from behind after he had moved his vehicle to the shoulder and proceeded at a low rate of speed in response to mechanical problems. But in Mosely, the truck driver was not held to be negligent as he was driving on the highway shoulder when the accident occurred, and:

"... was not creating a threat for other motorists.... The decision was reasonable in the circumstances."


  • Duhaime, Lloyd, Speeding Law
  • Duhaime, Lloyd, Traffic Law
  • Highway Traffic Act, Revised Statutes of Ontario 1990, Chapter H-8
  • Highway Traffic Act, Statutes of Saskathewan 1986, Chapter H-3.1
  • Lave, C., "Speeding, Coordination, and the 55 MPH Limit", published in the December 1985 edition of the American Economic Review, Volume 75, No. 5, page 1163.
  • Libman, R., Libman on Regulatory Offences in Canada (Earlscourt Legal Press: Salt Spring Island, 2008)
  • Moseley v Spray Lakes Sawmills 194 AR 384 (1990, ABQB)
  • Motor Vehicle Act, Revised Statutes of British Columbia 1996, Chapter 318
  • Motor Vehicle Act, Revised Statutes of New Brunswick 1973, Chapter M-17
  • R v Chamberlain, 49 MVR 3d 92 (NBQB, 1999)
  • Traffic Safety Act, Revised Statutes of Alberta 2000, Chapter T-6