How Effective?

An integrated package of measures is most likely to be successful in speed management. The typology of drivers suggests that different approaches and messages may be required for different segments of the driving population and consideration should be given to drivers risk threshold and perceptions of their own capability in relation to the driving task.


  • Although road safety campaigns containing risk information may be useful in deterring drivers en masse, these campaigns may be ineffective in tackling the worst offenders.

(Fylan et al, 2006)

  • There may be scope to develop knowledge of the consequences of high speed - only around a quarter of drivers disagreed with fact based statements that associate speed with collision risk.Ø Drivers significantly overestimate the time gained by driving 10mph faster than - and time lost by driving 10mph more slowly than - 60 mph, suggesting there is scope for education in this area.

(Stradling et al, 2008)

  • Implementation intentions have the potential to break unwanted habits and help individuals behave in line with their goal intentions. Linking critical situations in which a driver is tempted to speed with goal-directed responses to resist the temptation resulted in decreases in self-reported speeding. The use of a volitional help sheet is easy to administer and cost effective to help change habits.

(Brewster et al., 2015)

Speed awareness courses

  • The Department for Transport, in conjunction with the Road Safety Trust, has commissioned an evaluation of the National Driver Offender Retraining Scheme (NDORS) speed awareness course. The work is expected to be completed in 2016. The main objective of this research is to conduct an impact evaluation of the course scheme, including the impact of the courses on reoffending/reconviction rates and collisions.

(Department for Transport, 2016)

  • Evidence suggests that, to be effective, speed awareness courses should be based on information and education, use credible and forceful materials and involve interactive group discussions.

(Fylan et al, 2006)

  • An evaluation of the National Speed Awareness Course demonstrated that the course produces changes in key psychological predictors of speeding, e.g. attitudes and intentions. For example, after the course, participants believed they would gain less enjoyment from speeding, positive attitudes towards speeding decreased, and negative attitudes towards speeding increased.Ø Participants who responded at follow-up (3 months post course) reported that they had changed their driving after attending the course, notably driving more slowly, being more aware of the road environment and of their speed, and feeling less stressed while driving.

(Brainbox, 2011)

Speed Limits

  • Setting appropriate, safe, and credible speed limits is an absolute priority for a good speed management policy.

(ETSC, 2010)

  • Speed limits are an important dimension of road safety management, but driving at speeds in excess of the posted speed limit is common in Britain. Speed limits should not be set in isolation and should be used alongside other speed-management methods, such as engineering measures, education, training, publicity and enforcement.

  • The appropriate speed for a section of road takes account of safety, mobility and environmental considerations as well as the impact of the speed on the quality of life for people living alongside the road.

  • Most drivers speed at some time in their lives and some regularly break speed limits. In uncongested conditions about half of traffic exceeds the speed limits on built-up roads and motorways but this proportion has fallen in recent years.

  • Speeding on residential roads is seen as less acceptable than speeding on motorways – especially by men – and generally younger drivers are more likely to speed than older drivers.

(Box, 2012)


  • Many drivers are deterred from speeding if they believe they are going to be detected, though a ‘hard core’ minority with positive attitudes to speeding are not deterred.

(Corbett et al, 2008)

  • Research suggests that penalties, or the fear of penalties, can reduce speeding but penalties need to be perceived to be fair.

(Webster and Wells, 2000)

  • Drivers adapt to changes in the amount of speed enforcement carried out by speeding less when enforcement increases and speeding more when enforcement is reduced.

(Elvik, 2015)

There has been much debate regarding the effectiveness of safety cameras. Several reviews have been published which provide some evidence that safety cameras are effective at reducing speeds and casualties. The evidence is presented in the Safety Camera synthesis (main topic of Compliance and the Law) - http://www.roadsafetyobservatory.com/KeyFacts/compliance-and-law/safety-cameras


  • A variety of engineering measures have been shown to reduce speeds, and examples of these are provided below.

  • Highway measures to reduce speed are usually most effective if there is a reason for drivers to slow down e.g. for a bend. Physical measures appear effective in urban environments, peripheral hatching effective in rural areas and vehicle activated signs on approaches to junctions.

(Jamson et al, 2008)

  • The potential for reducing accidents by means of general engineering and enforcement strategies for speed restraint appears greater for urban roads than rural roads. On rural roads, speed management measures that target specific problems or roads are more likely to be cost-effective than ‘blanket’ measures.

(Taylor et al, 2000)

  • Research evaluating the impact of 20 mph zones with traffic calming found considerable reductions in the average speed, with large falls in collisions. Twenty mph speed limits without traffic calming have lower benefits in speed and casualty reduction.

(cited in AECOM, 2009)

Further evidence on the effectiveness of 20mph zones and limits is contained in the Traffic Calming synthesis (main category of Roads - http://www.roadsafetyobservatory.com/KeyFacts/roads/traffic-calming).

  • The Rural Demonstration Project (King and Chapman, 2010) trialled a variety of initiatives, across 4 counties, in order to reduce rural road casualties. Several measures were effective in reducing speeds on rural roads, whilst others appeared to increase speeds. Examples include:

    • Strategic planting at village entries reduced traffic speed (mean speed tended to reduce by about 1.5 per cent). (Norfolk)

    • The removal of vegetation had the effect of increasing vehicles’ speeds. There was a slight but statistically significant increase in the proportion of vehicles being driven at higher speeds. (Norfolk)

    • When reducing the speed limit from 60mph to 50mph on certain road sections, the 85th percentile vehicle speeds fell by around 3 mph. (Lincolnshire).

    • A programme of enhanced verge maintenance on sections of the B1188 and A15 in Lincolnshire saw an increase in both vehicle speeds and collisions.

(King and Chapman, 2010)

    • Recent UK research indicates advisory Intelligent Speed Adaptation (ISA) has the potential to reduce excessive speeding (and therefore reduce the number and severity of road casualties):

    • Advisory ISA was fitted to cars and buses in a recent trial in Lancashire:·

    • When drivers chose to activate the system, their speeding was reduced by 30 per cent on 30 mph roads and by 56 per cent on 70 mph roads.

    • Being able to use the system (but not necessarily having it active) reduced speeding on 30 mph roads by 18 per cent and on 70 mph roads by 31 per cent.·

    • For car drivers aged 25 and below, active use of advisory ISA resulted in a reduction in speeding of 22 per cent on 30 mph roads and 37 per cent on 70 mph roads.

(Lai et al, 2012)


  • Date Added: 03 Apr 2012, 08:12 AM
  • Last Update: 26 Jan 2017, 05:21 PM