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Jay W. Preston, CSP, PE, CMIOSH, President and CEO

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Human Factors

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Safety Subject Information:

Accident investigations and analysis show that the overwhelming majority of falls and similar injuries occur at level changes. Debris and other materials as well as holes and low-level obstacles like wheelstops can result in such transitions.

The presence of potholes, speedbumps, Botts dots, wheelstops, and other surface irregularities can cause falls and similar incidents due to the inadequate footing and the unexpected nature of the irregularity. A person can catch a toe on the edge of such a feature and trip to fall to be injured.

Wheelstops are also known as tire stops, parking bumpers, parking stops, and dead men.  The terms refer to a long block of concrete, wood or another material that is about the size of a curb (6" by 6")  to impede the movement of vehicles.  Frequently they are held in place by pegs of rebar.

The presence of wheelstops in a parking lot should be avoided where possible due to the tripping hazard that they pose. They should only be used to protect a fixed object, and only where pedestrians are unlikely to travel. Where they must be used, they should be painted "traffic yellow" to provide a daylight warning, and be adequately highlighted and illuminated to be seen during dark hours.

The practice of lining up a wheel stop end with the midline between parking stalls should be avoided. Such lining up of a wheel stop end guarantees that the wheel stop obstacle will protrude into pedestrian traffic areas one foot or more when cars are reasonably parked. If wheelstops must be used they should be installed such that their ends are set back from stall lines by at least one foot. Where "hairpin" lines are used to designate stalls, the wheel stop must not protrude from the stall beyond the stall side of the hairpin lines.  The ASTM Standard requires a clear pedestrian area of at least three feet.

In no case should wheelstops be used adjacent to a marked pedestrian walkway. A pedestrian straying over a line would then be exposed to the trip and fall hazard. This is particularly true where the marked walkway is designed for handicapped access.

The presence of a wheel stop in what would be a pedestrian path. makes a route dangerous. Walkways and entries can be protected from vehicle encroachment in a way that does not create the low level tripping hazard of wheelstops. Guard posts, bollards, a wider walkway, or massive foundations can serve admirably.

Barrier posts or "bollards" are an acceptable option. These have the advantage that they do not protrude into the dark shadows between parked cars or into a reasonable pedestrian path.  They are also high enough to be far more visible than wheelstops when no cars are parked. Care should be taken to make the bollards at least 42 inches high, at least five inches in diameter, and paint them vividly. They can be used bi-directionally, and they are more durable than wheelstops. The bollards can also serve as bases for signage.

Copyright 2000 - 2011, Jay W. Preston.  Distribution permission granted when this notice is printed in full.  For questions or comments: contact prestonoidaol.com.  The J-P, Plus Design and SAFETYBIZ. are registered service marks of Jay William Preston. Permission for use of specific Safety Subject Information is only granted when this notice is printed in full and Preston has been contacted by phone, fax, or email prior to use.