An arterial road or arterial thoroughfare is a high-capacity urban road that sits below

highway A highway is any public or private road or other public way on land. It includes not just major roads, but also other public roads and rights of way. In the United States, it is also used as an equivalent term to controlled-access highway, or ...

s on the

road hierarchy A road hierarchy is a system for categorizing roads. Road networks worldwide are typically organized according to one or more schemes: * ''Functional classification'' reflects a road’s intended role, balancing mobility (efficient through mo ...

in terms of

traffic flow In 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 devices), with the ai ...

and

speed 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 non-negative scalar quantity. Intro ...

. The primary function of an arterial road is to deliver traffic from collector roads to highways or expressways, and between urban hubs at a relatively high level of service. Therefore, many arteries are

limited-access road A limited-access road, known by various terms worldwide, including limited-access highway, partial controlled-access highway, and expressway, is a highway or arterial road for high-speed traffic which has many or most characteristics of a contro ...

s 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 highways. 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.

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. The handbook also states that 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.

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 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 b ...

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 ar ...

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 (road), intersection (or level crossing, railroad crossing) is safely clear of vehicles and pedestrians before contin ...

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 highways 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 ranges from four lanes to ten or more.

Environmental issues

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

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

generation,

noise pollution Noise pollution, or sound pollution, is the propagation of noise or sound with potential harmful effects on humans and animals. The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems.Senate Publi ...

and

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

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