Towns, villages and cities should be places where people are free to travel in ways that are safe, sustainable, healthy and fair. Unfortunately, in many places in the UK, inappropriate speed limits where people live, work and play make movement dangerous, particularly for cyclists and pedestrians, including children and the elderly.

Faster traffic speeds make communities more dangerous. Speed also affects people’s perceptions of danger, and can be a determining factor in whether people decide to walk or cycle.

Unfortunately, many drivers break speed limits in built-up areas. A Brake and Direct Line survey revealed four in 10 drivers sometimes break 30mph speed limits by at least 10mph. A quarter (24%) admitted to doing this at least once a month.[xi]

It is widely understood that 20mph is the most appropriate maximum speed limit for built up areas where people live, work and play.

Safe

Effective speed management, including through low limits in communities, is considered central to a ‘safe system’ approach to road safety, crucial to reducing casualties and enabling walking and cycling. The safe system principle acknowledges that people can make mistakes behind the wheel and that there are known limits to ‘the capacity of the human body to absorb kinetic energy before harm occurs’. Within a safe system, effective speed management works holistically with vehicle design, road infrastructure and road user behaviour, to produce an overall safety effect greater than the sum of its parts.[xii]

Speed limits give road users information about the type of road and likely hazards on it, such as the presence of people on foot and bicycles in communities.[xiii]

The World Health Organisation has emphasised the need for 20mph limits, stating that in areas where ‘motorised traffic mixes with pedestrians, cyclists, and moped riders, the speed limit must be under 30 km/h (20mph)’ due the vulnerability of these road users.[xiv]

Slower speeds mean stopping in time for a child

In 2016, 69 children under 15 were killed and 2,033 were seriously injured on British roads: more than five children seriously hurt or killed every day.[xv]

20mph limits are important for protecting children, who often make mistakes when using roads. Research has found children cannot judge the speed of approaching vehicles travelling faster than 20mph, so may believe it is safe to cross when it is not.[xvi]

A limit of 20mph gives drivers a much improved chance to stop in time for a child. If a child runs into the road three car lengths ahead of a vehicle travelling at 30mph (48km/h), the driver will still be travelling at 28mph (45km/h) when they hit the child. A driver travelling at the more appropriate speed of 20mph or slower gives the driver just the necessary time to avoid hitting the child, providing they are paying attention, have well-maintained brakes, and are driving in dry conditions.[xvii]

20mph limits reduce traffic speed

Analysis of traffic casualties in London from 1986-2006 showed 20mph zones, introduced with traffic calming measures (such as speed humps and chicanes) reduced deaths and serious injuries by 42%.[xviii]

However, with traffic calming measures, such as speed humps, carrying a considerable expense to install, signs-only limits can be considered a “cheap option” by local authorities and central government. While certainly cheaper than the introduction of physical measures, there are still considerable costs involved with implementing 20mph limits. Many of these costs, however, could be eliminated through a change in regulations, without the need for additional primary legislation. Often the largest cost of the implementation of 20mph limits is signage.

A study by the TRL in 1998 found that the impact of different measures were as follows for moving from 30 to 20mph speed limits[xix]:

  • Physical traffic calming measures reduce both mean and 85th percentile speeds by around 10mph;
  • Speed cameras reduce mean 85th percentile speeds by 5mph;
  • Flashing, vehicle-activated signs reduce mean and 85th percentile speeds by 4mph;
  • Signs-only measures in general have a mean reduction of 2mph, but for 20mph limits this is 1mph;
  • In areas with signs-only limits, public awareness and enforcement campaigns can have a further reduction of around 3mph.

Public acceptance of 20mph limits

Increasingly, people understand the value of 2omph limits. In one recent survey, three quarters of people (69%) were in favour of 20mph in residential areas and 50% in favour of enforcing this limit and slowing traffic through the installation of speed bumps on key local routes.[xx]

Sustainable

Each year in the UK, around 40,000 deaths are attributable to exposure to outdoor air pollution, with more linked also to exposure to indoor pollutants.[xxi] According to the World Health Organization’s database, 88% of urban dwellers live in cities which do not comply with the Air Quality Guidelines.[xxii] Vehicles on the road have contributed significantly to levels of emissions in urban areas, with current estimates suggesting that in the UK alone, cars are producing 13% of our CO2 emissions.[xxiii]

Driving at more than 20mph in towns and villages also means more speeding up and slowing down, increasing carbon emissions.[xxiv] Slowing down traffic to a top speed of 20mph enables smoother driving, decreasing emissions, and also encouraging and enabling people to swap from driving to cycling.[xxv] This can have a big impact on a community's air quality as well as contributing to reduced carbon emissions.

In 2016, the British Social Attitude Survey asked recipients if they agreed with the statement that ‘the road is too dangerous to cycle on’, 59% of respondents agreed.[xxvi]

Healthy

In the UK it is currently estimated that one in six deaths can be attributed to inactivity[xxvii], and Minister for Health, Jeremy Hunt MP, described childhood obesity within England as a ‘national emergency’. Daily physical activity is hugely important for maintaining health and research has shown that half an hour of brisk walking, daily, can cut heart disease, improve muscle strength[xxviii], and combat depression and other mental illnesses[xxix].

Active travel, most obviously walking and cycling within and between communities, provides a key opportunity for this physical exercise. Unfortunately, many people, especially those with children, are put off walking and cycling due to traffic speeds. A Brake and Churchill survey found almost six in ten UK parents (59%) had witnessed drivers speeding close to their child’s school or nursery.[xxx]

In 2016, including short walks, people walked an average of 198 miles, or around 4 miles per week, and a quarter (25%) of journeys and just 3% of miles travelled in Britain are now on foot.[xxxi]

Similarly, cycling still only accounts for a very small proportion of journeys in Britain, and road safety is a major factor in putting many people off. Just 2% of journeys and 1% of miles travelled are made by bike.[xxxii]

Women, non-cyclists and older age groups showed higher levels of concern over roads being too dangerous to cycle on.[xxxiii]

Introduction of 20mph limits helps people to undertake active travel; walking and cycling levels rose in most areas of in Bristol after a pilot 20mph limit was introduced.[xxxiv]

Fair

Streets are an important aspect of local communities, people rely on them on a daily basis for travel, shopping, social interaction and work. Unfortunately, the volume and speed of motorised traffic within an area can negatively impact on local communities, reducing social interaction within neighbourhoods and encouraging an increasing sense of isolation in residents in higher speed areas.[xxxv] A 2016 study in Malmo, Sweden, stressed that urban spaces could be crucial to the social development of a community and the building of social bonds between residents.[xxxvi]

A case study in Bristol found people living on a street experiencing a heavy volume of high speed traffic had fewer friends than those who lived in the quieter residential area surveyed.[xxxvii] Results which are largely similar to previous studies on the subject, stretching back over the years.[xxxviii]

When traffic is slowed to 20mph in communities, research shows people are friendlier with their neighbours, feel safer in their area, and take part in more community activities.[xxxix] Research has also found 20mph limits boost the economic sustainability in the area, as safer areas for walking and cycling are seen as more desirable areas to live, boosting local businesses[xl] and increasing the value of homes in these areas.[xli]

Implementation

The default speed limit for roads in built up areas is 30mph in the UK, a limit set down in law by the Road Traffic Regulation Act (1984).[xlii] Therefore, 30mph is automatically in place on roads within communities, known as ‘restricted roads’, unless another speed limit is in force and signs clearly displayed.

Local speed limits can be set by local traffic authorities where ‘local needs and conditions suggest a speed limit which is different from the respective national speed limit’. Therefore, local councils have the authority to implement 20mph speed limits within communities where they believe it will make a difference to safety, the environment or other aspects of the community.[xliii]

The Department for Transport’s guidelines for Setting local speed limits (2013) clearly state that the implementation of a 20mph limit should be ‘evidence-led and self-explaining’, aimed at encouraging self-compliance and kept under constant assessment by the local authority. The guidelines recommend that before altering the default speed limit to, for example, 20mph, local authorities should carry out a study of types of crashes and their severity within the area selected for the change. This approach is aimed at ensuring that the speed limit assigned is appropriate for the area in which it is implemented. A speed limit is designed to reflect the environment that the road is located in, and any report produced should show clear benefits in implementing a change (to 20mph) before it is enacted by a local authority.[xliv]

When implementing 20mph in a region, local councils must decide between implementing a 20mph zone or a 20mph limit. The difference between the two is[xlv]:

  • A 20mph zone: An area of road with repeater signs and physical traffic calming measures, including speed humps and road narrowing. These are the more expensive out of the two options to implement and, where present, usually cover smaller areas.
  • A 20mph limit: An area marked by 20mph repeater signs, with no physical traffic calming measures in place. This option is seen as cheaper than 20mph zones, however, the cost of multiple repeater signs is not insignificant.

When motorised traffic mixes with pedestrians and cyclists, travelling speeds should be under 20mph

World Health Organisation