Shoulder (road)
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A hard shoulder, or simply shoulder, is a reserved area by the verge of a road or motorway. Generally it is kept clear of all traffic. In the event of an emergency or breakdown, a motorist can pull into the hard shoulder to get out of the flow of traffic and obtain an element of safety. A hard shoulder also allows some extra flexibility should a motorist need to take evasive action, as it is a buffer area between the main thoroughfare and the edge of the road. Emergency vehicles such as ambulances and police cars may also use the shoulder to bypass traffic congestion. These uses lead to the alternate names breakdown lane and emergency lane.
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[edit] General characteristics
The shoulder is usually slightly narrower than a full traffic lane. In some cases, particularly on old rural roadways, shoulders do not exist or are made of gravel rather than hard asphalt or concrete. These are known as soft shoulders in comparison. Because the road surface changes at that point, they are less safe if they need to be used for emergency maneuvers, so modern practice is to build a hard shoulder whenever possible. To save money, the hard shoulder is sometimes not paved to the same thickness as the through lanes, so if vehicles were to attempt to use it as a through lane regularly, it would rapidly deteriorate. The shoulder also often collects various bits of debris that can make driving there unsafe.
Drivers will sometimes drift into the shoulder when being overtaken by passing vehicles, particularly on two-lane roads. However, it is extremely unsafe, as well as often illegal, to abuse the hard shoulder by 'undertaking' passing vehicles that are nearer the centre of the road. (Some roads and expressways have a hard shoulder that is of such a narrow width that 'undertaking' is impossible.) In some jurisdictions in the United States and Canada, buses are allowed to drive on the shoulder to pass traffic jams, which is called a bus-only shoulder or bus-bypass shoulder; the term "bus-only shoulder lane" is incorrect from a technical and legal standpoint [1]. In Ontario, Highway 403 had its shoulders between Hurontario Street and Erin Mills Parkway widened in 2003 so they serve a dual-purpose as bus lanes and accident lanes; in the Minneapolis-St. Paul region of Minnesota, over 250 miles of shoulder have been designated for use by busses. [2]. In other cities, the concept has been extended to passenger cars; in the Boston Metro Area, cars are allowed to use the shoulder as they would a normal lane during morning and evening rush hours.
On many roads, the shoulder disappears for short periods, particularly near exits and sometimes when going across or under bridges where the cost savings outweigh the disadvantages of not having the shoulder. However, some roads have a narrow shoulder for significant distances. This makes it difficult for large vehicles to pull into the hard shoulder altogether. The Jingjintang Expressway in northeastern China is an example of this phenomenon. Its hard shoulder is 2.4 metres wide, which is not wide enough for some automobiles. As a result, some motorists are unable to fully exit the mainline when they need to pull over, so they end up in a position that is halfway in the rightmost lane and halfway in the hard shoulder. The result is often a traffic jam and occasionally something worse.
[edit] Characteristics in various countries
[edit] Republic of Ireland
Full-width hard shoulders are provided on most new, upgraded (from the 1980s onwards), and major national roads in the Republic of Ireland, especially on wide two-lane and dual-carriageway roads (the shoulders on most 2+1 roads are narrow however). The road surface is usually different, using reddish coloured surfacing that does not need to withstand heavy traffic volumes. On older roads, simple resurfacings, or short route sections, the surface may be identical to the main road lanes.
The hard shoulder is usually demarcated by road markings in the form of a single dashed yellow line with the addition of yellow cat's eyes. On motorways, and at critical points on other routes (e.g. between junctions or sliproads, or beneath overpasses) a solid yellow line is used, denoting additional restrictions on usage of the hard shoulder. At junctions and sliproads, the yellow line peels away into the turn, with a dashed white line (with green cat's eyes) denoting a lane division following the main route (i.e. in most cases the road remains the same width, and a turn lane takes the place of the hard shoulder).
In the 2000s, Bus Éireann coaches were allowed use the hard shoulders on national roads into Dublin. However, dedicated bus lanes are now present on sections of some routes, such as the N7 Naas Road, and such use of actual hard shoulder (i.e. demarkated with yellow rather than white dashed line) is not universal.
[edit] United States
In the USA, the right-hand shoulder is separated by a solid white line, and the left-hand shoulder (if the road is a divided highway) is separated from the main road by a solid yellow line. On freeways in foggy parts of California, there is an obvious break in the line of the shoulder before every exit; this is to help drivers find their exits in heavy fog.
[edit] United Kingdom
Full width hard shoulders are usually provided only on motorways and are usually 3.3 metres wide, but there are exceptions. Some motorways do not have hard shoulders at all (for example the A6144(M) and the A57(M)) and there are a small number of dual carriageway A-roads which do possess hard shoulders (for example, parts of the A1, A2 and A27). Hard shoulders are always marked with a reflectorised solid white line which is 20 cm wide and is provided with a rumble strip. A line of red cat's eyes is also used, and is placed to the side of the line.
Sometimes, a hard shoulder will be coloured differently (usually red) to that of the main carriageway lanes. This is sometimes because the hard shoulder has not been resurfaced recently. The red colouring of many shoulders is because red surfacing was cheaper than black when the surface was laid. Sometimes, hard shoulders are coloured red to make it stand out from the main carriageway (for example on many of the motorways in Lancashire.)
On many modern non-motorway roads, a hard strip is provided. These are usually 1 metre wide, and are bounded by thinner solid white lines, and often without a rumble strip.
On 12 September 2006, an experiment began to allow motorists on an 11-mile stretch of the M42 motorway, near Birmingham, to drive on the hard shoulder. Special signage, new laybys and a variable speed limit have been put in place to improve safety[3].
