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, signings and markings help to regulate and moderate driver behaviour.

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 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).
The UK Highways Agency is currently investigating the effect of chevron road markings at motorway junctions. Meanwhile, 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).

	= Weakest possible response,		= strongest possible positive response
	= Weakest possible negative response,		= strongest possible negative response

= No response

Short and long run demand responses

	= Weakest possible response,		= strongest possible positive response
	= Weakest possible negative response,		= strongest possible negative response

= No response

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.

	= Weakest possible positive contribution,		= strongest possible positive contribution
	= Weakest possible negative contribution		= strongest possible negative contribution

= No contribution

Expected impact on problems

Problem	Scale of contribution	Comment
Congestion-related delay		By reducing time spent and km driven searching, and by possible encouragement of walking, cycling and public transport use arising out of pedestrian, cyclist and public transport signing
Congestion-related unreliability		By reducing time spent and km driven searching, and by possible encouragement of walking, cycling and public transport use arising out of pedestrian, cyclist and public transport signing
Community severance	-	-
Visual intrusion		So long as signing and markings are sensitive to the surrounding environment
Lack of amenity	-	-
Global warming		by reducing traffic-related CO2 emissions
Local air pollution		By reducing the emissions of NOx, particulates and other local pollutants by car
Noise		By reducing car traffic volumes
Reduction of green space	-	-
Damage to environmentally sensitive sites		Where signs or markings are used to moderate/regulate driver behaviour in sensitive areas
Poor accessibility for those without a car and those with mobility impairments		By regulating/moderating driver behaviour and, in the case of pedestrian, cyclist and public transport signing, improving information and guidance
Disproportionate disadvantaging of particular social or geographic groups	-	-
Number, severity and risk of accidents		By regulating/moderating driver behaviour and providing road users with required en route information
Suppression of the potential for economic activity in the area	-	-

	= Weakest possible positive contribution,		= strongest possible positive contribution
	= Weakest possible negative contribution		= strongest possible negative contribution

= No contribution

Expected winners and losers  

	= weakest possible benefit,		= strongest benefit
	= weakest possible disbenefet,		= strongest possible disbenefit

= neither wins nor loses

Barriers to implementation

= minimal barrier,

= most significant barrier