What is Accessibility?
Accessibility is the ability of people to reach places and services and the ability of places to be reached by people and goods.
Separate planning for people, places or transport will not necessarily ensure good access. A combined approach is needed to ensure that all of the barriers to access are overcome. Good planning of accessibility checks that everyone has the ability to reach the services and closes all identified gaps. These approaches are used by:
- Retailers, who plan access to ensure that customers can reach their locations.
- Transport operators, who plan access to ensure that their networks cover as many travel needs as possible.
- Local government, who plan access to ensure that everyone in society can reach essential services.
The three main components of access are affected by many factors:
- Transport: All of the types of transport needed to make a door to door journey.
- Land: All of the places where services are located. Services placed at locations the local population can reach are often described as accessible.
- People: Ensuring there are opportunities for all people. Do people know where things are? Do they feel safe? Do they have the skills to travel?
Accessibility has been planned successfully when people, services and transport interact well together.
How Accessibility is Measured
The simplest measure of accessibility is travel time to the nearest location of a service:
- Travel time indicates the general convenience of making a journey. Calculations vary in complexity, from applying a set speed to the shortest path through a network, to the use of public transport timetables. Other factors may be relevant, in addition to travel time, such as money cost or an individual's perception of journey difficulty.
- Nearest location ensures minimum standards for access to services. In practice access to a range of similar services is often important - for example, hospitals do not all offer the same treatments, shops do not all offer the same quality of product.
Accessibility analysis is commonly broken down into types of:
- Service, for example, retail, healthcare, education and employment. Analysis tends to focus on such "essential" services because Accessibility Planning was first used to tackle social exclusion. However the same methods can be applied to any service offered at specific geographic locations.
- Transport, for example, private car, public transport, walk and cycling. The availability of each type (mode) of transport varies. Some households have no private car available, some people are unable to walk far, some locations have no public transport links.
There is no one universally agreed single measure of accessibility.
Uses of Accessibility Data
Since the mid-2000s, local accessibility data has been calculated for the whole of Britain. More data has been published for England than for Scotland and Wales. Accessibility is typically calculated for each of the smallest census boundary areas (called Lower Layer Super Output Areas, or Data Zones in Scotland - each of which has a population of between 1,000 and 3,000 people).
Accessibility data can be used to meet immediate, practical needs, such as locating the nearest coffee house and planning a journey to reach it. However, the analysis of accessibility data has far more strategic uses, for example:
- How easy will it be to reach essential services if you move home?
- Which hospital sites should healthcare services be provided at?
- Will potential customers easily be able to reach a new retail location without new transport services?
More specifically, UK government formally requires consideration of accessibility:
- Local authority access plans require consideration of accessibility indicators.
- Developers of land need to consider the accessibility requirements of planning policy guidance.
For further details of the raw data data available, previous published analysis, and how to obtain custom accessibility analysis, see Reports.
Travel Time Maps
Variations in local accessibility can be explored using our travel time maps. These are available for the whole of Great Britain. They show public transport travel times to the nearest location of each essential service. Additional data is available for each local area, showing travel time by other modes of transport, plus (for England) an index showing the range of choice of locations for each service.
For example, access to hospitals from east (right) of Manchester appears far worse (red) than to the south (lower left, green). Further investigation reveals that Tameside General Hospital (upper centre) is not terribly easy to reach by public transport from much of Tameside (lower centre). To learn more about our maps, see Maps.
Who We Are
We have undertaken much of the accessibility data processing and analysis on behalf of government, and worked with other interested organisations on the topic of accessibility planning for over 10 years.