Conventional Signs & Markings

This measure was updated by INSTITUTE FOR TRANSPORT STUDIES (ITS) in 2014 under the CH4LLENGE project, financed by the European Commission.

Conventional signs and markings are visual means of providing information, guidance and instruction to travellers during their journey. Their objective is to promote the safe and efficient use of the transport system. Both signs and markings impart information but also have a role in the management of traffic. In many cases, signs and markings are used in conjunction with each other.

Signs and markings include:

• Upright signs - various types of upright signs with textual or graphical images, for information, regulation or warning
• Road markings – provided to channel traffic and to convey warnings, regulatory requirements or basic information
• Miscellaneous signs – including traffic signals, temporary signs and lamps to identify refuges or provide additional warning in cases of dangerous obstructions.

Common standards for signs and markings exist to help ensure that travellers can easily understand signs wherever they might be travelling.

Conventional direction signing can provide benefits to car users, and other traffic, by reducing journey lengths and travel times; direction signing can also be used to divert traffic away from environmentally sensitive routes. 
Signs and markings are also important in road safety by providing information necessary to make safe decisions while travelling.

There is little direct evidence on their effectiveness but it is known that direction signing can help to reduce congestion, by reducing driver confusion, journey lengths and travel times, while regulatory signing can influence congestion by reducing the number of accidents that impede flows and generate delays. 

Regarding markings on the road surface, research has shown that longitudinal road markings, including chevrons, can reduce speeds and accidents considerably. Overall, it can be concluded that markings are cost efficient, and instrumental in easing congestion and promoting safety.

Description

Conventional signs and markings are visual means of providing information, guidance and instruction to travellers whilst en route. Their objective in the main is to promote the safe and efficient use of the transport system. As such, their design must be good and their maintenance given priority. Highway authorities have continuous maintenance programmes with contingency plans for areas susceptible to fog, ice and snow.

The word ‘conventional’ is used to distinguish types of signs and markings which have been used for many years from more modern types. Thus ‘signs’ in this case are taken to be roadside fixed signs with painted text or symbols: other types, such as Variable Message Signs (VMS) are dealt with in a separate section. Markings are lines and other symbols which are painted on the road surface or close to it (e.g. on the kerb). Both may impart information but both are often also concerned with managing traffic. For convenience they are dealt with together here under the general heading ‘information measures’.

Signs and markings are a vital component of almost every traffic management scheme and, as an intrinsic part of a design, they must be considered at the same time as the physical components of a scheme, and not added afterwards. In many cases signs and markings are complementary to each other, e.g. parking yellow lines and accompanying signs indicating the related regulations. Markings on the road can often be seen when vertical signs are rendered less visible by poor visibility or heavy traffic and, conversely, vertical signs may be seen in some cases when road markings are obscured by snow or ice.

The messages conveyed by signs and markings should be as clear and concise as possible as they will generally need to be seen, read, understood and acted upon in a relatively short period of time. To assist with this, many countries develop sets of standard types of signs and, under the Vienna Convention (1968), most countries throughout Europe have adopted a similar style of sign to facilitate a general understanding wherever travellers might be in Europe. However, information on the impacts of signs and markings is particularly limited at present.

Terminology

Types of signing and marking

Signs and markings are generally divided into three main groups:

1. Upright signs - various types of upright signs with textual or graphical images, divided into three main types:
   1. Information signs – giving information about routes and directions, distances, places and facilities of particular interest;
   2. Regulatory signs – giving notice of restrictions or prohibitions on the speed, movement and waiting times for vehicles;
   3. Warning signs – giving warning of hazards ahead.
2. Road markings – provided to channel traffic and to convey warnings, regulatory requirements or basic information, they are sometimes supplemented by studs incorporating reflectors; most are white but yellow is widely used (in the UK at least) for markings related to parking and other colours are increasingly used, including red (e.g. London’s ‘Red Routes’), blue (e.g. London’s cycle super highways) and green (e.g. Edinburgh ‘Greenways’). Road markings convey regulations, guidance or warnings mainly, but not exclusively, in the following ways:
   • Lane lines to guide traffic and achieve efficient utilisation of road space;
     Stop and ‘give way’ lines;
   • Rumble strips which are sometimes used to reinforce awareness of the above; 
   • Warnings of vertical deflections (e.g. speed humps); 
   • Carriageway edge lines and kerb markings to indicate parking, stopping and loading regulations
   • Chevrons to channel traffic at junctions, influence speeds or available capacity.

3. Miscellaneous signs – including traffic signals, temporary signs associated with, for example, special events or road works, flashing beacons to provide additional warning, cones to define routes around obstacles or road works, cylinders to denote the temporary division of a carriageway, and lamps to identify refuges or provide additional warning in cases of dangerous obstructions.

The circumstances in which these different signs and markings are permitted or required to be used is, for the UK, set out in the Road Signs Regulations and General Directions (RSRGD). In general, all signs on the highway must conform to government guidelines relating to their location, size, colour, the information provided and reflectivity, though there are circumstances when special signs might be approved directly by the Minister.

Common standards for signs and markings exist to help ensure that travellers can easily understand signs wherever they might be travelling. Where signs do not conform to the appropriate regulations, or where they are unauthorised, road users may be distracted, endangering road safety.

Variable message signs (VMS) are a further set of signs, using electronics technology to provide updatable information, and are dealt with separately due to their different character. Furthermore, traffic signals are another means of conveying messages and again they are dealt with separately, under Urban Traffic Control, owing to their different character.

In addition to roadside signs and signals, further information is increasingly being provided by in-vehicle guidance systems either by the radio, via Radio Data Systems (RDS) or via on-board units (OBUs). For the future, there are likely to be linkages between roadside information and in-vehicle information, e.g. speed limit reminders or even enforcement in association with electronic speed limiters.

Technology

Signs and markings are relatively low-tech facilities. Upright signs usually consist of a legend – text, diagram or symbol, picture or some combination of these - carried by a sign face which may be of sheet or other applied material (e.g. paint or print) mounted on a substrate – usually made from aluminium - and fixed to a frame and supported by a post or posts. Other types of miscellaneous signs are generally of a more simple construction and self supporting. In the UK, British Standard BS873 lays down the performance requirements for the various elements of road traffic signs.

Specialist computer software is available to assist with sign design, route planning, location plans, manufacturing, signs inventory and maintenance.

Why introduce conventional signs and markings?

Conventional direction signing can provide benefits to car users, and other traffic, by reducing journey lengths and travel times; evidence suggests that around 6% of travel time may be accounted for by poor routeing, and that inadequate destination signing may as much as double the time spent searching for unfamiliar destinations (Jeffery, 1981). 

Conversely, direction signing can be used to divert traffic away from environmentally sensitive routes; however, familiar drivers are unlikely to respond to such measures.

Signing and markings also have a vital role to play in road safety, in providing information necessary to make safe en route decisions, in reminding drivers of the rules, regulations and guidelines they should follow en route and in providing warning of hazards etc.

Static direction signs are also important measures for providing information for cyclists and pedestrians. Good signage can be used to enhance the use of cycle priority routes and to improve access within pedestrian areas for disabled pedestrians.

Static direction signs may also be the main element in voluntary lorry routeing schemes.

Sign design may also form part of an overall corporate image for street furniture within a city or region. For example, where there has been selective deregulation of signing and markings this has sometimes led to greater variety and “branding” of signs, such as the directional signs for pedestrians in the City of London.

As pressure from higher traffic levels increases the requirement to make more efficient use of the road network - including encouraging other modes – it is argued that road signs must become increasingly important.

General effectiveness

Direction signing can help to reduce congestion, by reducing driver confusion, journey lengths and travel times. Evidence suggests that around 6% of travel time is wasted following inappropriate or indirect routes, and inadequate signing may double the amount of time spent searching for unfamiliar destinations (Jeffery, 1981). The total time lost by drivers being unable to find their way costs about £35m a year in the UK (Palmer, 1998).

Regulatory signing can influence congestion by reducing the number of accidents that impede flows and generate delays. Signs and marking aimed at slowing speeds tend to be less effective at reducing the frequency of road accidents than engineering measures (as discussed in Accident Remedial Measures), but they are still important. For example, distance markers which help drivers to maintain safe headways on motorways can reduce accidents by more than 50% (Elvik and Vaa, 2003), as shown in the table below. 

Effect of Various Markings (Elvik and Vaa, 2003)

Research in the US has shown that longitudinal pavement markings reduce accidents by 21% and edge lines on rural two-lane highways lead to a reduction of 8%. Comparing the costs and benefits of conventional marking materials, etc on different classes of roads gave benefit to cost ratios ranging from 21:1 to 103:1. The study concluded that markings are cost efficient, instrumental in easing congestion and indispensable safety measures in periods of poor visibility (Miller, 1992).

Chevrons have been widely used to adjust capacity and improve performance. In the US, the chevron markings on the I94 in Wisconsin (left) were effective in reducing speeds, smoothing flows and reducing accidents. 85th percentile speeds fell by 17mph in the four months before and after installation, and accidents fell from 14 in the two years before, to eight in the two years after implementation (Drakopoulos and Vergou, 2003).

Evidence from examples such the A24 between Leatherhead and Dorking in Surrey, UK, have shown that reducing two lanes to one with white line hatching can improve safety and smooth flows. Markings and a lower speed limit were introduced in 1991 to tackle accidents caused by speeding on a narrow, curved section of road. Between 1984-87 there were 43 accidents and this fell to 9 between 1992-94 (Surrey County Council, 2004), and there has been no impact on throughput or congestion.

Demand impacts

It is estimated that time lost through people unable to find their way amounts to an annual cost of £35m a year in the UK (Palmer, 1998).

Short and long run demand responses

Expected impact on key policy objectives

It is asserted that the “careful provision of prescribed signs and markings can make a considerable contribution to the safe and efficient operation of the highway network” (IHT, 1997). This is by providing road users with the information they require en route so that appropriate routes are taken, regulations are observed and hazards are avoided.

Expected impact on problems

Expected winners and losers

Barriers to implementation

Since most such signs and markings have been in use for several decades there have been few detailed studies of their impact.  Such evidence as is available is cited under the First Principles Assessment above.

Contribution to objectives

In the absence of empirical evidence, the table from first principles is repeated here.

Contribution to problems

In the absence of empirical evidence the table from first principles is repeated here.

Appropriate contexts

Signs and markings are equally appropriate in all contexts.

Adverse side effects

There are unlikely to be significant adverse side effects, except where signs divert traffic to alternative routes.

BSI (1983). BS 873-1:1983 Road traffic signs and internally illuminated bollards. British Standards Institute (also BS873 Nos 2 to 8 on this and related topics)

Department of Transport (1994) The design and use of directional informatory signs; ltn1/94, HMSO, London.

Department of Transport (1995) Traffic signs to tourist attractions and facilities in England; cr3/95, London.

Department for Transport (2002) Traffic signs regulations and general directions, DFT, London.

DFT (2002) Traffic Signs Manual, Department for Transport London.

Drakopoulos, A. and Vergou, G. (2003). An evaluation of the converging chevron pavement marking pattern installed on the I94 at the Mitchell Interchange south to west ramp in Milwaukee County, Wisconsin, AA Association for Traffic Safety.

Elvik, R. and Vaa, T., (2003) The Handbook of Road Safety Measures. NY, Amsterdam, Elsevier science (Forthcoming)

IHT (1997) Transport in the Urban Environment, Institution of Highways and Transportation, London.

Jeffery, D.J. (1981). The potential benefits of route guidance. LR997. Crowthorne. TRRL.

Miller, T.R., (1992a) Benefit-cost analysis of lane marking, Transportation Research Record, Issue: 1334, December 1992. pp 38-45.

Palmer, D. (1998). Road signs their contribution to integrated transport. Highways and Transportation, March 1998

Surrey County Council (2004). Data for the A24 Gibbons Grove Roundabout to Swanworth Lane provided by Surrey County Council. (Pers Comm to MVA 25/6/04)

TRB (2000) Highway Capacity Manual 2000, Transportation Research Board, Washington DC.