People have the right to be involved in discussions and make informed decisions about their care, as described in NICE's information on making decisions about your care.

Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off‑label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

The evidence statements underpinning the recommendations are listed in appendix C.

See also the evidence reviews, supporting evidence statements and cost-effectiveness modelling.

PHIAC considers that the recommended measures are cost effective. For the gaps in research, see appendix D.


The recommendations in this guidance should be implemented as part of a broader strategy that includes driver and public education and enforcement activities.

Note that in November 2010, we published a NICE guideline on unintentional injuries: prevention strategies for under 15s.

The recommendations in this guidance cover 20 miles per hour (mph) limits, 20 mph zones and engineering measures to reduce speed or make routes safer, reflecting the evidence identified and expert discussions. The absence of recommendations on any other measures is a result of a lack of evidence that met the inclusion criteria for the evidence reviews. It should not be taken as a judgement on whether or not any other measures are effective and cost effective.


This guidance uses the term 'unintentional injuries' rather than 'accidents', since 'most injuries and their precipitating events are predictable and preventable' (Davis R, Pless B (2001) BMJ bans 'accidents'. Accidents are not unpredictable. BMJ 322: 1320–21). The term 'accident' implies an unpredictable and therefore unavoidable event.

Engineering measures to reduce speed or make routes safer comprise physical features such as speed humps, chicanes or changes in traffic priority (that is, changes in the right for traffic to proceed). These may be used on single roads or across a larger area.

20 mph limits are imposed using signs at the start and end of roads covered by the limit and reminder signs at points in between (terminal and repeater signing).

20 mph zones are areas where engineering measures must be used to slow traffic.

Whose health will benefit?

The recommendations aim to help children and young people aged under 15, although there may also be benefits for the wider population.

Recommendation 1 Health advocacy and engagement

Who should take action?

  • Directors of public health and other health professionals with responsibility for preventing or treating injuries.

  • Local strategic partnerships.

What action should they take?

  • Ensure a senior public health position includes leading on, and responsibility for, the health sector's involvement in injury prevention and risk reduction.

  • Support and promote changes to the road environment as part of a broader strategy to prevent injuries and the risk of injuries.

  • Support coordinated working between health professionals and local highways authorities to promote changes to the road environment.

Recommendation 2 Needs assessment and planning

Who should take action?

Local highways authorities.

What action should they take?

Work with other partners to introduce engineering measures to reduce speed as part of a broad strategy to prevent injuries and the risk of injuries (see recommendation 1).

These measures should be:

  • developed after considering data on risk of injury (such as traffic speed and volume) and injuries (including levels of casualties, their age, the groups involved and where they occur)

  • designed and constructed in line with current good practice guidelines and case studies (such as the Department for Transport's manual for streets 2), and determined by local context and the characteristics of the site (including physical limitations such as geological considerations)

  • designed taking into account all road users (not just car users), including vulnerable road users (such as pedestrians, cyclists and those with impaired mobility)

  • developed using effective processes of community engagement to seek the views of children, young people, their parents and carers (as outlined in the NICE guideline on community engagement) and with involvement of other interested parties such as the emergency services and local businesses

  • implemented based on local priorities for modifying the transport infrastructure

  • evaluated for their effect in terms of reducing the risk of injury and reducing the number of actual injuries

  • evaluated for any unintended consequences, such as the impact on the number of people walking or cycling or on injury rates in neighbouring streets.

Recommendation 3 Measures to reduce speed

Who should take action?

  • Local highways authorities.

  • Local strategic partnerships.

What action should they take?

  • Introduce engineering measures to reduce speed in streets that are primarily residential or where pedestrian and cyclist movements are high. These measures could include:

    • speed reduction features (for example, traffic-calming measures on single streets, or 20 mph zones across wider areas)

    • changes to the speed limit with signing only (20 mph limits) where current average speeds are low enough, in line with Department for Transport guidelines.

  • Implement city or town-wide 20 mph limits and zones on appropriate roads. Use factors such as traffic volume, speed and function to determine which roads are appropriate.

  • Consider changes to speed limits and appropriate engineering measures on rural roads where the risk of injury is relatively high, in line with Department for Transport guidance.

  • Take account of the factors identified in recommendation 2 when introducing measures.

  • When introducing engineering measures to reduce speed, consider promoting smooth driving and speed reduction to minimise pollution (see the NICE guideline on air pollution: outdoor air quality and health).