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 dev ...

and

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (ma ...

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

or expressways, and between urban centres at the highest level of service possible. As such, many arteries are limited-access roads, or feature restrictions on private access. Because of their relatively high accessibility, 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 collector roads 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 expressways 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 level of service, 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 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 intersections 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 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 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 ot ...

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 ma ...

and surface runoff 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