Rat running or cut-through driving refers to the use of secondary roads or residential side streets instead of the intended main roads in urban or suburban areas. People do it to avoid heavy traffic, lengthy traffic signals or other obstacles, even where there are traffic calming

Traffic calming

Traffic calming is intended to slow or reduce motor-vehicle traffic in order to improve the living conditions for residents as well as to improve safety for pedestrians and cyclists. Urban planners and traffic engineers have many strategies for traffic calming...

 measures to discourage them, or laws against taking certain routes. Rat runs are frequently taken by motorists familiar with the local geography. They will often take such short cuts to avoid busy main roads and intersections. The term may have arisen from associations with the rat race

Rat Race

A rat race is a term used for an endless, self-defeating or pointless pursuit. It conjures up the image of the futile efforts of a lab rat trying to escape while running around a maze or in a wheel...

 or from similarities between the driving routes used and those taken by rats running through a maze.

Rat running is controversial. It is sometimes opposed by homeowners on the affected streets, as some people regard it as a disturbance of their peace. Sometimes it affects house prices. Authorities often try to prevent it, but enforcement is difficult. Rat running is sometimes fought by installing traffic calming devices, such as all-way stop

All-way stop

An all-way stop is an intersection system used predominantly in the United States of America, Canada and South Africa where traffic approaching it from all directions is required to stop before proceeding through the intersection...

s, speed hump

Speed hump

A speed hump is a rounded traffic calming device used to reduce vehicle speed and volume on residential streets. Humps are placed across the road to slow traffic and are often installed in a series of several humps in order to prevent cars from speeding before and after the hump...

s, traffic circle

Traffic circle

A traffic circle or rotary is a type of circular intersection in which traffic must travel in one direction around a central island. In some countries, traffic entering the circle has the right-of-way and drivers in the circle must yield. In many other countries, traffic entering the circle must...

s, and rumble strip

Rumble strip

Rumble strips, also known as sleeper lines, are a road safety feature that alert inattentive drivers to potential danger by causing a tactile vibration and audible rumbling, transmitted through the wheels into the car body...

s, by making some streets one-way, or by blocking off certain intersections. Some places, including Montgomery County

Montgomery County, Maryland

Montgomery County is a county in the U.S. state of Maryland, situated just to the north of Washington, D.C., and southwest of the city of Baltimore. It is one of the most affluent counties in the United States, and has the highest percentage of residents over 25 years of age who hold post-graduate...

, Maryland, Maryland Heights

Maryland Heights, Missouri

Maryland Heights is a second-ring west-central suburb of St. Louis, located in St. Louis County, Missouri, United States. The population was 27,472 at the 2010 census. The city was incorporated in 1985. Edwin L. Dirck was elected the city's first mayor. Mark M. Levin has been City Administrator...

, Missouri, and parts of Minneapolis

Minneapolis, Minnesota

Minneapolis , nicknamed "City of Lakes" and the "Mill City," is the county seat of Hennepin County, the largest city in the U.S. state of Minnesota, and the 48th largest in the United States...

, have banned turning on certain streets during rush hours to prevent rat running.

Some motorists keep their rat runs secret in order to prevent others from clogging up the roads they routinely use.

Side street usage

Motorists familiar with an area sometimes use side streets or other smaller roads that run in the same direction as the main road on a parallel route. They are generally local people who know these streets and the pros and cons of using them as alternatives to the main road.

Red light avoidance

In some places, motorists avoid stopping at a red light by turning on to a side street or into a parking lot to bypass it.

In some countries, red lights can be avoided by turning right on red

Right turn on red

Right turn on red, or simply right on red, is a principle of law permitting vehicles at a traffic light showing a red signal to turn right when the way is clear, in a country with right-hand traffic...

 (or left in drive-on-the-left countries), making a U-turn, and then turning right or left again back on to the street on which the motorist was traveling. This may require less time than waiting for the light to turn green.

Traffic jam avoidance

Some motorists exit and then re-enter a freeway or motorway at the same junction, or use lanes designated for exiting and merging, in order to pass stationary traffic.

Some large streets are separted from parallel small residential streets only by a small strip where homeowners park their vehicles. These streets can be used to bypass traffic jams.

Preventing rat running

When a major event draws a large volume of traffic, local police sometimes monitor or block secondary roads to prevent motorists from the event crowd from using such streets to avoid the traffic.

Since the 2000s, a number of U.S. states, including Georgia

Georgia (U.S. state)

Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

 and Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

, some smaller U.S. jurisdictions, and some parts of the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 have passed or tried to pass laws restricting rat-running in certain communities to maintain peace and privacy for residents. Even where signs clearly mark places where rat-running is prohibited, however, enforcement is difficult and prosecutions are rare.

Many communities combat rat running by installing traffic calming features such as chicanes, speed tables, speed cushions, kerb extensions, cobbled sections, and various other measures. Other communities install physical barriers that completely block through-traffic along routes prone to rat running. One of the most extensive uses of this strategy is found in Berkeley, California

Berkeley, California

Berkeley is a city on the east shore of the San Francisco Bay in Northern California, United States. Its neighbors to the south are the cities of Oakland and Emeryville. To the north is the city of Albany and the unincorporated community of Kensington...

, where dozens of concrete barriers throughout the city block shortcuts, while still allowing cycling. In Northern Virginia

Northern Virginia

Northern Virginia consists of several counties and independent cities in the Commonwealth of Virginia, in a widespread region generally radiating southerly and westward from Washington, D.C...

, shortcuts are discouraged by the construction of dead end street

Dead End Street

Dead End Street is a 1982 film directed by Yaky Yosha. Inspired by a true story, it is about a young prostitute who participated in a documentary about her efforts to abandon the streets, only to commit suicide hours before the movie was to be broadcast....

s, communities with no outlet, and winding roads designed to confuse, making navigation through the neighborhoods more difficult and time-consuming.