The first design consideration concerns the number of spaces and the types of vehicle required to be accommodated, as this may dictate to a large extent the type of layout to be adopted in the space available.
Accurate calculation of the number of car spaces required for a new facility is not possible, as the pattern and level of use will vary from one site to another. However, it is worth comparing figures for other similar sites and locations to obtain an idea of the right order of provision. Seasonal and weekly fluctuations in use also need to be assessed and
some judgement made as to whether to cater for the busiest periods or average demand. On many sites there may be peak usage on certain public holidays that is significantly higher than the rest of the year. It is unlikely to be economic to cater for this demand, and so the provision of overflow parking may be a better option.
A formula has also been used to calculate the expected number of car spaces. It provides a rough guide in the absence of other information, but depends on the assumptions used to provide the initial figures:
where, V=number of spaces required, v=number of day visits, p=average number of people per car, s=average length of stay, and h=average daily period for which the site will be in use.
The parking requirement may be complicated by other factors. In many areas coaches may be used to bring visitors to a particular beauty spot. In others, trailers for boats, kayaks, horses or trailer caravans may need to be accommodated. Such large or unwieldy vehicles have less flexible requirements for turning or manoeuvring, and take up more space per unit.
(a) A simple layout where a side loop is made from the access road. Bays to
accommodate varying numbers of cars are made along either side of the loop. (b) A loop that can operate on a one-way system from a main access or public road. The circular shape would be varied in practice to take account of local terrain, trees, rocks etc. (c) This version contains several sub-loops accommodating many more cars, and is suitable for busier sites. It should operate on a one-way system, and can be laid outfor either left-hand or right-hand driving sides.