A motorway service area is any government-approved facility designed to rest drivers using the motorway network. They are run entirely by private operators but regulated by the Department for Transport through Circular 01/2008 (in England only, though similar policies apply across the UK). They are either infill or core, and online or offline.
This whole site deals with various aspects of them, which is why they're not explained in great detail here.
Any facility designed to serve travellers could claim to have had an influence on the motorway service area, but the closest relative is the coaching inn, which set up at the crossings of major routes to rest horses and their owners. They were usually located every few miles and offered food, accommodation and stables.
See also: 50 Years of Motorway Services
When the M1 opened, Watford Gap was always considered to be a 'service area' (although it is often discounted as it was so dissimilar to today's services). This was designed by the government and run by a private operator, Blue Boar, and provided the mould for all future services.
Motorway services must provide the following facilities 24 hours a day:
- Two hours free parking
- Free toilets and baby-changing facilities
- A free picnic and children's play area
- Snacks and hot drinks
- Access for those carrying out duties on behalf of the Secretary of State for Transport
They are usually located at 30-mile intervals.
Road signs are dealt with in detail on the Motorway Signs page.