Slip lane

Last updated

In road design, a slip lane is a road at a junction that allows road users to change roads without actually entering an intersection. [1] Slip lanes are "helpful ...for intersections designed for large buses or trucks to physically make a turn in the space allotted, or where the right turn is sharper than a 90 degree turn." [2] Slip lanes may reduce congestion and "t-bone" motor vehicle collisions, but they increase the risk for pedestrians, cyclists and horse riders who cross the slip lane.

Contents

Illustration (left-hand traffic): the blue vehicle in the slip lane must normally give way to the green and red vehicles once they are on the major road. Sliplane.png
Illustration (left-hand traffic): the blue vehicle in the slip lane must normally give way to the green and red vehicles once they are on the major road.

Some intersections that are controlled by lights offer a slip lane, which allows users to bypass the lights when they turn. That helps ease congestion and improves journey times, as people turning do not have to stop at the light but can continue at the same speed. [3] There are two types of slip lanes at intersections: slip lanes that end and require traffic to merge to join the main road, and slip roads that continue onto the main road as another traffic lane.

Terminology

They are known as a "filter lane" in the United Kingdom. In right-turn countries, they may be called "channelized right-hand turn lanes."

Rules

In Australia, before entering a slip road, drivers must look to ensure that their blind spots are clear of other motorists, cyclists, and pedestrians. Drivers must then give way to any pedestrians crossing the slip road. Before joining the main road from a slip road, drivers must give way to all other traffic even if it is faced with a give-way or with other traffic controls. [4]

Pedestrians

A right-turn slip lane in the United States (center of photo), including a pedestrian crossing. Northwest corner of intersection of Rt. 57 and Rt. 31.jpg
A right-turn slip lane in the United States (center of photo), including a pedestrian crossing.

In countries such as the United Kingdom in which partial conflicts between pedestrians and vehicular traffic are not permitted, slip lanes can be used as part of a "walk with traffic" facility. Normally, pedestrian signals in the UK operate on a full pedestrian stage in which all traffic is held at red, and all pedestrian crossings are given a green signal. With a slip lane, pedestrians can cross to the triangular island during the vehicle red phase and cross the road while the traffic from their approach has a green. [5]

The Federal Highway Administration (FHWA) in United States has indicated that "to accommodate safe pedestrian crossings", intersections should be designed "using tight curb radii, shorter crossing distances, and other tools... While right-turn slip lanes are generally a negative facility from the pedestrian perspective due to the emphasis on easy and fast vehicle travel, they can be designed to be less problematic." [6]

In right-turn countries, designers of right -turn slip lanes may try to increase pedestrian safety by including a range of features. These may include "a raised "island" for pedestrians with a curb and ramps for wheelchair users. To encourage drivers to slow down for crossing pedestrians, edge lines or painted cross-hatching may be used to "narrow the [driver's] perceived width of the lane." [7] As well, pedestrian safety in the crosswalk may be improved with "high-visibility crosswalk striping, flashing beacons, and/or signage" and raised crosswalks. Flashing "warning beacons may be desirable in locations where there are high traffic volumes and vehicle speeds." [8] Some states in the United States require a stop sign at slip lanes to control entry to the main roadway. [9]

The organisation Strong Towns argues that slip lanes exist to only prioritise the speed of motor traffic and calls for the removal of slip lanes on local streets. [10]

When poorly designed, slip lanes can be a dangerous design element. For reasons of urban design and pedestrian safety, many road-controlling authorities are actively removing them in urban and suburban settings. [11] [12] Slip lanes may need to be removed if considerations such as pedestrian safety grow to a point that they override the desire to facilitate free passage for cars. [13] [14] "Slip lanes reduce drivers’ awareness of crossing pedestrians because they are led to focus on the traffic stream into which they are merging, and also impair visibility of the traffic stream because of the angle of approach." [15] As well, "[s]lip lanes also greatly increase crossing complexity for pedestrians and cyclists, by increasing total crossing distance, requiring judgement about crossing fast-moving traffic without the benefit of a traffic signal." [16] To minimise risks of collision, slip lanes can be shaped to enter the traffic flow at an angle higher than the 45 degrees that is shown in the sketch. Such lanes are called high-entry angle slip lanes. [17]

Further reading

See also

Related Research Articles

<span class="mw-page-title-main">Traffic</span> Phenomenon of movement by humans on foot or using vehicles

Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads/sidewalks) for travel and transportation.

<span class="mw-page-title-main">Roundabout</span> Traffic intersection

A roundabout, a rotary and a traffic circle are all, with certain distinctions between them, a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.

<span class="mw-page-title-main">Intersection (road)</span> Road junction where two or more roads either meet or cross at grade

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 are often delineated by gores and may be classified by road segments, traffic controls and lane design.

<span class="mw-page-title-main">Pedestrian crossing</span> Place designated for pedestrians to cross a road, street or avenue

A pedestrian crossing is a place designated for pedestrians to cross a road, street or avenue. The term "pedestrian crossing" is also used in the Vienna and Geneva Conventions, both of which pertain to road signs and road traffic.

<span class="mw-page-title-main">Traffic light</span> Signaling device to control competing flows of traffic

Traffic lights, traffic signals, or stoplights – also known as robots in South Africa and Namibia – are signalling devices positioned at road intersections, pedestrian crossings, and other locations in order to control the flow of traffic.

<span class="mw-page-title-main">Road traffic safety</span> Methods and measures for reducing the risk of death and injury on roads

Road traffic safety refers to the methods and measures used to prevent road users from being killed or seriously injured. Typical road users include pedestrians, cyclists, motorists, vehicle passengers, and passengers of on-road public transport.

<span class="mw-page-title-main">Jaywalking</span> Pedestrian crossing of a carriageway outside of a crosswalk

Jaywalking is the act of pedestrians walking in or crossing a roadway if that act contravenes traffic regulations. The term originated in the United States as a derivation of the phrase jay-drivers, people who drove horse-drawn carriages and automobiles on the wrong side of the road, before taking its current meaning. Jaywalking was coined as the automobile arrived in the street in the context of the conflict between pedestrian and automobiles, more specifically the nascent automobile industry.

<span class="mw-page-title-main">Jughandle</span> Diversionary road used for making turns at an intersection

A jughandle is a type of ramp or slip road that changes the way traffic turns left at an at-grade intersection. Instead of a standard left turn being made from the left lane, left-turning traffic uses a ramp on the right side of the road. In a standard forward jughandle or near-side jughandle, the ramp leaves before the intersection, and left-turning traffic turns left off of it rather than the through road; right turns are also made using the jughandle. In a reverse jughandle or far-side jughandle, the ramp leaves after the intersection, and left-turning traffic loops around to the right and merges with the crossroad before the intersection.

<span class="mw-page-title-main">Road junction</span> Location where two or more roads meet

A junction is where two or more roads meet.

<span class="mw-page-title-main">Turn on red</span> Traffic principle

Turn on red is a principle of law permitting vehicles at a traffic light showing a red signal to turn into the direction of traffic nearer to them when the way is clear, without having to wait for a green signal.

<span class="mw-page-title-main">Variations in traffic light operation</span>

In traffic engineering, there are regional and national variations in traffic light operation. This may be in the standard traffic light sequence or by the use of special signals.

<span class="mw-page-title-main">All-way stop</span> Road intersection with stop signs on all approaches

An all-way stop – also known as a four-way stop – is a traffic management system which requires vehicles on all the approaches to a road intersection to stop at the intersection before proceeding through it. Designed for use at low traffic-volume locations, the arrangement is common in the United States, Canada, Mexico, South Africa, and Liberia, as well as in a number of, usually rural, locations in Australia where visibility on the junction approaches is particularly poor. The stop signs at such intersections may be supplemented with additional plates stating the number of approaches.

<span class="mw-page-title-main">Road collision types</span> Overview of the various types of road traffic collision

Road traffic collisions generally fall into one of five common types:

<span class="mw-page-title-main">HAWK beacon</span> Traffic control device

A HAWK beacon is a traffic control device used to stop road traffic and allow pedestrians to cross safely. It is officially known as a pedestrian hybrid beacon. The purpose of a HAWK beacon is to allow protected pedestrian crossings, stopping vehicular traffic only as needed. The HAWK beacon is a type of traffic control alternative to traffic control signals and/or where an intersection does not meet traffic signal warrants.

<span class="mw-page-title-main">Road signs in the United States</span> Road and traffic signs utilized in the United States

In the United States, road signs are, for the most part, standardized by federal regulations, most notably in the Manual on Uniform Traffic Control Devices (MUTCD) and its companion volume the Standard Highway Signs (SHS).

<span class="mw-page-title-main">Road signs in South Korea</span>

Road signs in South Korea are regulated by the Korean Road Traffic Authority.

Road signs in Canada may conform to the Manual of Uniform Traffic Control Devices for Canada (MUTCDC) by the Transportation Association of Canada (TAC) for use by Canadian jurisdictions. Although it serves a similar role to the MUTCD from the US Federal Highway Administration, it has been independently developed and has a number of key differences with its American counterpart, most notably the inclusion of bilingual (English/French) signage for jurisdictions such as New Brunswick with significant anglophone and francophone population, and a heavier reliance on symbols rather than text legends.

<span class="mw-page-title-main">Glossary of road transport terms</span>

Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.

<span class="mw-page-title-main">Stroad</span> Type of thoroughfare

A stroad is a type of thoroughfare that is a mix between a street and a road. Common in the United States and Canada, stroads are wide arterials that often provide access to strip malls, drive-throughs, and other automobile-oriented businesses. Urban planners have criticized stroads for their safety issues and poor efficiency. While streets provide access to shops and residences at safe traffic speeds, and roads can efficiently move traffic at high speed and volume, stroads pose dangers to drivers and pedestrians and are also prone to congestion.

<span class="mw-page-title-main">Crosswalks in North America</span>

Crosswalks in the United States and Canada are normally found at intersections, though sometimes may be found mid-block. Crosswalk installations must follow the regulations specified in the Manual on Uniform Traffic Control Devices (MUTCD). At signalized intersections, crosswalks may have pedestrian signals which display symbols to mandate when pedestrians may cross the street.

References

  1. "Pedestrians crossing slip lanes" (PDF). Main Roads Western Australia. September 2002. Retrieved 8 November 2015.
  2. Davis, Stephen Lee (5 November 2019). "Slip Lanes Would Never Exist if We Prioritized Safety over Speed". Strong Towns.
  3. Davis, Stephen Lee (5 November 2019). "Slip Lanes Would Never Exist if We Prioritized Safety over Speed". Strong Towns.
  4. "Road Rule Changes". cota-act.org.au. Archived from the original on 8 February 2008.
  5. "Chapter 6, Traffic control". Traffic signs manual. London: Department for Transport, Northern Ireland. Department for Infrastructure, Scotland. Scottish Government, Wales. Welsh Government. 2019. ISBN   978-0-11-553744-8. OCLC   1134444798.
  6. Davis, Stephen Lee (5 November 2019). "Slip Lanes Would Never Exist if We Prioritized Safety over Speed". Strong Towns.
  7. "Pedestrian Safety Guide and Countermeasure Selection System". www.pedbikesafe.org. Federal Highway Administration. Retrieved 6 March 2024.
  8. "Pedestrian Safety Guide and Countermeasure Selection System". www.pedbikesafe.org. Federal Highway Administration. Retrieved 6 March 2024.
  9. "Pedestrian Safety Guide and Countermeasure Selection System". www.pedbikesafe.org. Federal Highway Administration. Retrieved 6 March 2024.
  10. "Slip Lanes Would Never Exist if We Prioritized Safety Over Speed". Strong Towns. 5 November 2019. Retrieved 5 January 2022.
  11. "Well Designed Right–Turn Slip Lanes". Federal Highway Administration.
  12. "Cities Are Replacing Dangerous Slip Lanes With Space for People". Streetsblog. July 2018. Retrieved 4 June 2019.
  13. "City Road Draft Master Plan" (PDF). Melbourne City Council. July 2015. Retrieved 8 November 2015.
  14. "Slip Lanes be gone". Matt L. 2 October 2015. Retrieved 8 November 2015.
  15. "B.C. Community ROAD SAFETY TOOLKIT" (PDF). www.nanaimo.ca. City of Nanaimo. Retrieved 7 March 2024.
  16. "B.C. Community ROAD SAFETY TOOLKIT" (PDF). www.nanaimo.ca. City of Nanaimo. Retrieved 7 March 2024.
  17. "Guidelines for the signing and layout of slip lanes" (PDF). NZ Transport Agency. November 1993. Retrieved 9 May 2017.