All-way Stops in Canada

There is a scourge afflicting North America to which the rest of the world has remained largely free. It is perceived as being the solution to a century's accumulation of problems relating to vehicle traffic, while in fact being almost totally ineffective. It increases vehicle operating wear and tear, fuel costs, pollution, noise and accident costs, yet everyone seems to want one.

It is the all-way stop.

All-way stops are routinely placed in Canadian cities due to political pressure from adjacent residents who insist on believing that they will make life safer for their communities. In fact they

decrease safety of pedestrians at the intersection, especially children,
increase the risk of rear-end crashes,
worsen delays at adjacent intersections by causing traffic to leave the intersection equally spaced,
increase noise to neighbouring properties,
increase speed away from the intersections, and
reduce respect for stop signs when drivers perceive a stop to be unnecessary in the absence of conflicting traffic.

In most countries outside of North America, stop signs are restricted to situations where coming to a stop is necessary because of severely limited sight lines.

Georgia Traffic Engineer Martin Bretherton Jr. reviewed over 70 technical papers. He concluded that before-after studies show multi-way stop signs do not reduce speeds on residential streets, but rather that unwarranted multi-way stops increased speed away from intersections. Multi-way stop signs create pollution, enforcement problems and poor stop compliance when drivers feel that the signs have no justification. Multi-way stop signs impose high vehicle operating costs (one study's estimate: $26/year/vehicle/day), longer than needed travel times, excessive fuel consumption and increased vehicle emissions.

Other researchers also find that the safety of pedestrians (especially small children) is decreased at multi-way stops. Pedestrians expect vehicles to stop, but many drivers run the "unnecessary" signs. Engine exhaust, brake, tire and aerodynamic noise all increase as cars brake and then accelerate up to speed. While the initial cost of installing stop signs is low, enforcement costs are high. Where unwarranted multi-way stops have been successfully removed with public support, results have included improved compliance at justified stop signs.

A 1991 study for the City of Toronto "determined that removing 480 unwarranted stop signs would save nine million litres of gasoline and eliminate 21,000 tons of air pollutants, producing a 5.5 percent reduction in emissions". Annual overall gasoline consumption and fuel costs associated with traffic at all-way stop-signs are substantial. According to the Ontario Ministry of Municipal Affairs and Housing, the additional gasoline consumed every day from one stop sign on a typical collector road is 25 litres. At a typical four-way stop, the annual emissions released collectively from the vehicles travelling through it are 657 kg hydrocarbons, 8760 kg carbon monoxide, 675 kg nitrogen oxide, and 65700 kg carbon dioxide.

A few Ontario municipalities, such as Ajax, are listening. In 2005, Windsor banned new all-way stops on transit routes and declared that all-way stops will not be used as a speed control measure and will not be allowed within 250m of other all-way stops or traffic signals. A few other municipal policies also state that all-way stops must not be used as a speed control measure. But, all are too frequently overridden by municipal councils.

To improve the sustainability and livability of our cities, political all-way stops must go.

John Sankey
other notes on community matters

Some References:

Bretherton, M., "Multi-Way Stops - The Research Shows the MUTCD Is Correct!", 1999 ITE Compendium of Technical Papers. Institute of Transportation Engineers, August 1999

Carl R. Dawson, Jr., "Effectiveness of Stop Signs When Installed to Control Speeds Along Residential Streets", Proceedings Southern District ITE Meeting, Institute of Transportation Engineers, Richmond, Virginia, April 1993.

City of Windsor Traffic Calming for Residential Areas Policy Paper September 2005

A summary of the US MUTCD (Manual of Uniform Traffic Control Devices): installation of an all-way stop should be based on a traffic engineering study to determine if minimum traffic volume or safety criteria are met. These intersections are often found where roads with equal traffic levels meet each other but the overall level of traffic present at the intersection does not justify a traffic light, or in a location where the right of way is otherwise unclear. An all-way stop may be justified if the intersection has a demonstrated history of crashes in a given period of a type susceptible to correction by installing an all-way stop. All-way stops may be used to provide a low-speed area for pedestrians to cross, where a cross street experiences considerable difficulty finding safe gaps due to heavy traffic volumes, or where traffic is frequently delayed by turning conflicts. Four-way stops are best used only between minor roads away from urbanized areas.