An arterial road or arterial thoroughfare is a high-capacity

urban Urban means "related to a city". In that sense, the term may refer to: * Urban area, geographical area distinct from rural areas * Urban culture, the culture of towns and cities Urban may also refer to: General * Urban (name), a list of people ...

road that sits below

freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...

motorway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms i ...

s on the

road hierarchy The road hierarchy categorizes roads according to their functions and capacities. While sources differ on the exact nomenclature, the basic hierarchy comprises freeways, arterials, collectors, and local roads. Generally, the functional hierarchy ...

in terms of

traffic flow In mathematics and transportation engineering, traffic flow is the study of interactions between travellers (including pedestrians, cyclists, drivers, and their vehicles) and infrastructure (including highways, signage, and traffic control devi ...

and

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...

. The primary function of an arterial road is to deliver traffic from

collector road A collector road or distributor road is a low-to-moderate-capacity road which serves to move traffic from local streets to arterial roads. Unlike arterials, collector roads are designed to provide access to residential properties. Rarely, juris ...

s to

freeways A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms i ...

expressways Expressway may refer to: *Controlled-access highway, the highest-grade type of highway with access ramps, lane markings, etc., for high-speed traffic. *Limited-access road, a lower grade of highway or arterial road. *Expressway, the fictional slide ...

, and between urban centres at the highest

level of service Level of service may refer to: * Levels of service in asset management * Level of service (transportation) in transportation and traffic * Something agreed on in a Service-level agreement A service-level agreement (SLA) is a commitment between a ...

possible. As such, many arteries are

limited-access road A limited-access road, known by various terms worldwide, including limited-access highway, dual-carriageway, expressway, limited access freeway, and partial controlled access highway, is a highway or arterial road for high-speed traffic which ...

s, or feature restrictions on private access. Because of their relatively high

accessibility Accessibility is the design of products, devices, services, vehicles, or environments so as to be usable by people with disabilities. The concept of accessible design and practice of accessible development ensures both "direct access" (i. ...

, many major roads face large amounts of land use and urban development, making them significant urban places. In traffic engineering hierarchy, an arterial road delivers traffic between

s and

. For new arterial roads, intersections are often reduced to increase

. In California, arterial roads are usually spaced every half mile, and have intersecting collector(s) and streets. Some arterial roads, characterized by a small fraction of intersections and driveways compared to most arterial roads, are also considered to be

in some countries and US states.

Definition

The'' Traffic Engineering Handbook ''describes "Arterials" as being either principal or minor. Both classes serve to carry longer-distance flows between important centers of activity. Arterials are laid out as the backbone of a traffic network and ''should'' be designed to afford the highest

, as is practical, as per the aforementioned "Traffic Engineering Handbook".

Development

The construction and development of arterial roads is achieved through two methods. By far the most common is the upgrading of an existing

right-of-way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

during subdivision development. When existing structures prohibit the widening of an existing road however,

bypasses Bypass may refer to: * Bypass (road), a road that avoids a built-up area (not to be confused with passing lane) * Flood bypass of a river Science and technology Medicine * Bypass surgery, a class of surgeries including for example: ** Heart bypas ...

are often constructed. Because of the placement and general continuity of arterial road corridors, sewers, water mains, conduits and other infrastructure are placed beneath or beside the roadbed.

Specifications

In North America, signalized

at-grade intersection An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections a ...

s are used to connect arterials to collector roads and other local roads (except where the intersecting road is a minor side street, in which case a

stop sign A stop sign is a traffic sign designed to notify drivers that they must come to a complete stop and make sure the intersection is safely clear of vehicles and pedestrians before continuing past the sign. In many countries, the sign is a red oc ...

is used instead). In Europe, large roundabouts are more commonly seen at the busier junctions. Speed limits are typically between , depending on the density of use of the surrounding development. In school zones, speeds may be further reduced; likewise, in sparsely developed or rural areas, speeds may be increased. In western Canada, where freeways are scarce compared to the rest of North America, flashing early-warning amber lights are sometimes placed ahead of traffic lights on heavy signalized arterial roads so the speed limits can be raised to speeds of over 80 km/h. These warning lights are commonly found on high-speed arterial roads in British Columbia. The width of arterial roads can range from four lanes to ten or even more; either as a

dual carriageway A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...

or sharing a common center lane, such as a

contraflow lane In transport engineering nomenclature, a counterflow lane or contraflow lane is a lane in which traffic flows in the opposite direction of the surrounding lanes. Contraflow lanes are often used for bicycles or bus rapid transit on what are oth ...

or as a central turning lane.

Environmental issues

As with other roadway environmental consequences derive from arterial roadways, including air pollution generation,

noise pollution Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is main ...

and

surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...

of water pollutants. Air pollution generation from arterials can be rather concentrated, since traffic volumes can be relatively high, and traffic operating speeds are often low to moderate. Sound levels can also be considerable due to moderately high traffic volumes characteristic of arterials, and also due to considerable braking and acceleration that often occur on arterials that are heavily signalized.

References

External links