Optimisation of car-park designs

Figure 1: An example of a basement carpark plan.

Plans for new urban developments (blocksof flats, offices etc.) very often include in-tegrated basement car parks. The valueof each car-parking is space very high in-deed — perhaps £100k in central London,although a more typical figure across theUK is £15k. In consequence, there is highvalue in trying to maximise the numberof spaces within a given car park, withthe constraint that some level of usabil-ity (size of spaces, limitations on vehiclemanouverability) must be respected. Atpresent, the layout of car parks is designedby an architect with CAD tools, and theresults may be extremely complicated (seeFigure 1) — yet there is no guarantee thatthe architect has achieved the maximum possible number of spaces.

Figure 2: Standard aisle widths for right-angledand herringbone parking patterns.

We seek automatic algorithmswhich will either replace the role ofthe architect (or more realistically,act as a decision support tool tohim/her). When provided with agiven floor shape (and locations ofentrances / exits), the algorithmsshould seek ways of populating it withthe maximum possible number of us-able car-parking spaces. There aredesign standards1 for spaces — 4.8m× 2.5m is considered to be the small-est that is feasible — although thespace must be longer than this if it is in a ‘parallel park’ configuration. Local authoritiesalso maintain design standards about the widths of aisles and so on — see Figure 2. Butthese need not need to be respected in a private car-park — so a fundamental encodingof constraints in terms of turning circles, swept areas etc. might allow for more inventivesolutions and a better utilisation of space, than adherence to the design standards’ rulesof thumb.

Finally — in practice, the car parking area is impeded by structural pillars whosepositions one might assume (for simplicity) are fixed. However, it would be useful if thealgorithms and procedures could incorporate a sensitivity analysis — e.g., to indicatethat an extra space would be possible if a pillar is moved a small distance.

1Car Park Designers’ Handbook, by J.D. Hill at al, Thomas Telford Ltd.

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