Car Parks: The Overlooked Slip Risk in Commercial Properties

Why Car Parks Are a Documented Liability Risk

Car parks are now a documented source of public liability claims in commercial property portfolios — not because of high pedestrian volume, but because they are among the least consistently managed pedestrian environments in any asset class.

Unlike foyers or retail entries, car parks are frequently treated as vehicle infrastructure first and pedestrian environments second. Yet many contain some of the highest-risk pedestrian conditions in a property: low light, moisture, slopes, surface transitions, contaminants, and unpredictable pedestrian movement.

When incidents occur, the consequences extend beyond injury. Claims, insurance scrutiny, compliance questions and maintenance accountability follow. In many cases, the warning signs were already there.

Why Car Parks Create Unique Slip Risks

Four conditions consistently drive slip risk in commercial car parks.

Vehicle moisture tracking creates persistent wet paths along wheel tracks and pedestrian crossing areas during wet weather. In busy commercial buildings, these conditions can persist for extended periods before cleaning staff respond. The risk concentrates where pedestrian traffic intersects with vehicle movement — near lift lobbies, stair entries and designated crossing zones.

Contamination from oil, fuel and tyre residue accumulates gradually. A surface may still appear clean while performing poorly under wet conditions. As contaminants build up, slip resistance deteriorates without obvious visual warning.

Surface transitions between different pedestrian environments are among the most underestimated risks. Changes in friction, lighting, moisture exposure and slope can occur within only a few steps — asphalt to coated concrete, textured ramps into smooth lift lobbies, painted crossings onto exposed aggregate, repaired sections adjoining older surfaces. These zones are where slips and loss of footing commonly occur.

Inconsistent cleaning compounds all of the above. Cost pressure within cleaning contracts can reduce frequency, mechanisation and preventative maintenance — particularly in basement environments that receive less visual attention.

Slip incidents in car parks rarely occur in isolation. They often trigger downstream costs including incident investigation, contractor reviews, reactive maintenance, insurance scrutiny, operational disruption and reputational exposure — particularly in premium commercial assets.

High-Risk Zones Cluster Around Designated Bays

Some of the highest-risk areas in commercial car parks are concentrated around designated pedestrian-use zones: accessible parking bays, EV charging stations, parent-with-pram parking, click-and-collect areas, pedestrian crossings, and lift and stair access points.

These areas combine directional change, distraction, loading activity, moisture and varying pedestrian speeds within confined spaces. Pedestrians are rarely fully attentive to the floor surface — many are managing traffic movement, phones, bags, children or trolleys.

From a public liability perspective, these are highly foreseeable pedestrian interaction zones. That increases the importance of both maintenance records and documented slip resistance testing.

Relevant Slip Resistance Requirements

HB 198:2014 Table 3B recommends a minimum P3 classification for undercover car parks under wet pendulum testing. External car park areas with gradients under 1:14 are generally recommended at P4, while steeper ramps may require P5 depending on slope and application.

These classifications apply to surfaces that may become wet or contaminated during normal use. A surface that achieved compliant results at installation may not continue to perform at the same level after wear, coating degradation, contamination or repeated patch repairs.

Verification Testing Is Now a Standard Requirement

An increasing number of clients now request verification testing after line marking, resurfacing or coating installation works — particularly where anti-slip treatments form part of contractor specifications or handover requirements.

In-situ testing under AS 4663:2013 uses the wet pendulum test to assess existing pedestrian surfaces under real-world conditions. For car park environments, wet pendulum is generally the primary applicable method. Dry floor friction testing is not appropriate for surfaces that are likely to become wet or remain contaminated during normal use.

This distinction matters. Specifying the wrong test method produces results that do not reflect actual in-service performance.

In legal, insurance and compliance contexts, methodology, documentation and reporting quality carry significant weight. CCTV coverage of slip locations is frequently limited, obstructed or too distant to establish environmental conditions at the time of an incident. Documented inspection, maintenance and slip resistance testing records often become the primary evidence.

Car Parks Are No Longer Low-Priority Areas

The combination of slopes, contamination, surface wear, moisture tracking and inconsistent maintenance creates conditions where risk develops gradually — often without obvious visual warning signs.

Testing to AS 4663:2013 helps facility managers, property owners and contractors understand how surfaces are performing in service, not simply how they appeared when originally installed.

Because when a claim occurs, the question is rarely whether the surface looked safe.

The question is whether it actually was.