Column Centres: In a modern car park there should be no columns to impede access to parking spaces. In basement car parks this is difficult but not impossible to achieve. Where the standard 7.2m grid is used, designers need to recognise that the notional advantage of allowing for three spaces, each of 2.4m width between column centres, is lost once real columns (400 x 400) are inserted - the space is reduced to 6.8m. Designers should allow for 7.2m (or other multiples of 2.4m) clear between column edges so that full width spaces are available to patrons.

Head Clearance: Flat ceilings are preferable in all car parks. Structural beams should not be located in the vicinity of parking spaces, and if this cannot be avoided then allowance must be made not only for the height of car roofs but also for the height of hatchback doors which swing up.

Intrusions: Where ramps intersect with floors at parking spaces, the design needs to ensure that tall pedestrians don't risk cracking their skulls, or that tall vehicles don't have their roofs removed. Plinths that catch opening car doors or walls that protrude into circulation pathways are design challenges and should be eliminated.

Number of Lanes: Most car parks of up to 500 spaces require only one entry lane - possibly with twin ticket dispensers - as they usually face a pinch point which effectively means that only one line of cars can actually navigate 20 metres after the entry barrier. A minimum of 2 exit lanes are required at all automatic car parks, to allow for the patron who loses their ticket and blocks a lane while staff deal with them.

Lifts: 13 person lifts are increasingly essential if any reasonable comfort is to be provided, and these need to be in pairs. Smaller lifts do not meet the needs of people with shopping trolleys or baby buggies or large bags/packages.

Lighting Standards: Old recommendations on internal lighting standards e.g. of 50 lux, have long ago been discarded by the industry and replaced by minimum standards of 100 lux and 250 to 350 lux at entrance/exits. White fluorescent bulbs provide the best quality of light. Tungsten lamps generally give yellow tints and leave "cave" effects unless used in high densities. Lighting in stairwells and lobbies need to be to a very high specification to minimise perceptions of personal isolation.

Lines of Sight: Personal security is greatly enhanced in car parks where lighting levels are high and clear lines of sight are designed into a facility e.g. at access points to lift lobbies, stair lobbies, at corners on pedestrian routes. In addition all doors, including lift doors, should have large glass panels, all walls should have large glass windows so patrons can check whether it is safe to pass through or not. Structural walls can have 'openings' cut into them, to increase natural light penetration and improve sight lines.

Main Lobbies: The main lobbies of public car parks need to be sufficiently large and well laid out to accommodate the very large peak flows of patrons from lifts, stairs and ground floor areas, who are going to/from their cars and stopping to pay for their parking at pay stations or customer service desks. In addition, the area should allow plenty of room for vending machines, public phones, seating areas, litter bins and appropriate signage.

Office/Kiosk: Modern car parks require proper accommodation for staff including canteen, toilets and lockers in addition to the CCTV, PC & printer, intercoms, safe, supply stores, customer service window, phone/fax, wet/dry cleaning room, ticket storage etc. A minimum of 30 square metres is required.

Ramp Widths: Ramps in car parks need to be a minimum of 3 metres, to avoid collisions between ramp walls and vehicles. Tight turning circles need to be avoided.

Routes: Vehicular and pedestrians routes need to be segregated e.g. by painted walkways and separate signage schemes. Designs need to allow for wheelchairs immediately adjacent to lift lobbies and without a need to cross vehicle routes. Cul-de-sacs are a driver's nightmare, and should be avoided or minimised.

Scale: The size or capacity of a car park needs to be directly related to the likely peak demands for parking in the immediate vicinity of the site. Patrons will not normal walk more than 180 metres from their car to their destination.

Signage: Modern car parks should include significant provision for large illuminated signs for both pedestrian routes and for vehicular circulation routes. Provisional costing sums of £50 per space are minimal.

Space Size: The dimensions of spaces need to relate to the size of the vehicles expected to use the facility. The current standard of 2.4m x 4.8m spaces is quickly being overtaken by increases in car sizes and the increased use of long doors which require more room to open properly.

Stairs: In all car parks, there are significant numbers of patrons who refuse to use lifts, and so all stairs should be designed to a high standard to accommodate this, or should be alarmed and only accessible in the event of a fire.

Usage: Busy short stay car parks in provincial towns can have an average stay of less than 60 minutes, while average stays in Dublin City Centre car parks are 2.5 to 3 hours. This can result in average cars per space of 8 to 10 per day in Wexford or Drogheda, while in Dublin it can be only 3 or 4 cars per space per day. Good barrier systems can accommodate 200 to 250 cars per hour.

Vehicle Alignment: At car park entrances and exits, it is essential to allow sufficient room for cars to enter the lane and then align themselves with entry ticket machines. This usually requires that there be at least two vehicle lengths (10m) of straight lane in front of the barrier. Lanes should be only as wide as likely vehicles require, as overly wide lanes mean that drivers cannot reach ticket dispensers from their cars.

Liam Keilthy
Parking Consultant