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Winter’s a game of risk

  • SIMA
- Posted: October 30, 2017
By George MelchIor, ASM
On average, more than 50,000 crashes occur in parking facilities annually, resulting in 500 or more deaths and more than 60,000 injuries, according to statistics from the National Safety Council and National Highway Traffic Safety Administration.

“Parking lots are intense driving environments that require both drivers and pedestrians to pay close attention,” states Deborah Hersman, the president and CEO of the National Safety Council.

At a time of low unemployment, booming retail and increased distraction for drivers and pedestrians, the nation’s parking lots are as perilous as ever. In the northern United States, slippery surfaces, low light, poor sight lines and encumbered parking lot circulation exacerbate the risk of costly damages and injuries that occur in parking lots. Accordingly, property owners should implement risk management strategies into their snow and ice management operations to mitigate the likelihood of crashes and injuries.

Mitigating actions eliminate or otherwise reduce the likelihood or severity of a risk. Therefore, property owners and their snow and ice management providers should take the time to identify the risks and define their likelihood and severity.

Common parking lot injuries
In general for all parking lots, based on my experience as a facilities manager and consultant, the top three risks for damage or injury in parking lots during winter are pedestrian slip and falls on ice, vehicle impact with pedestrian and vehicle impact with another vehicle.

Slip and fall. Of the three, slip and falls are the most likely to occur, especially in a parking lot. That is because icy conditions on the walking surface are not always obvious to visual detection for a pedestrian. Ice is difficult to see, especially black ice, and could even be concealed by snow. Pedestrians are usually watching for vehicles, and, as such, are not typically investigating the walking surface for patches of untreated ice. The average injury claim for a pedestrian slip and fall injury on ice in a parking lot is $18,000 to $30,000; and workers’ compensation claims are higher at $25,000 to $45,000 per claim.

Pedestrian-vehicle conflict. Pedestrian impact from vehicles is less likely to occur than a slip and fall but often results in a more severe injury. A driver traveling 10 mph in an icy parking lot at night will travel approximately 36 feet in the time they detect a pedestrian to the time they actually apply the brakes (detection-reaction time). Additionally, on an icy surface, the vehicle will skid 12 to 15 feet. That means that from the time a driver sees a pedestrian to the time they come to a complete stop, the vehicle would have traveled approximately 50 feet. To put that in perspective, in a typical parking lot, that is the width of over five parking spaces. Due to the energy of the vehicle, an impact with a pedestrian could cause severe and/or permanent injuries and even death. For those reasons, the typical injury claim for a pedestrian struck by a vehicle in a parking lot tends to be higher than those of slip and fall injuries, and have a wide average range between $45,000 and $100,000.

Vehicle-vehicle conflict. Injuries from vehicle collisions aren’t as frequent or severe as slip and falls and pedestrian-vehicle conflict; but vehicle damages can be costly, averaging $2,500 to $6,500. Of note, a lot of damages are worked out between drivers and are not reported, so the average financial damages are lower than this range. Rather, this range is the cost of damages drivers try to claim against a third party.

Risk cube
In defining risks, a risk cube can be a helpful aid. A risk cube (shown below) is a simple graphic on which you can plot an event based on perceived likelihood and severity, and can be used to inform mitigating tactics for those events. 

Illustration 1 is an example of a risk cube that includes the three most prevalent risks of damage or injury in a parking lot during winter. The objective of mitigation is to move the plotted risks down and to the left by reducing likelihood of occurrence or severity of damages, respectively. Because the damages resulting from all three of the risks previously identified are the result of a collision between two or more physical masses, reduction of severity may prove to be marginal. However, a variety of mitigating actions can reduce the likelihood of occurrence:

Preseason planning. Inspect parking lots and identify areas of known ponding, puddling and flow paths for stormwater and snowmelt. Designate those areas as ones requiring special treatment due to known water accumulation and resultant propensity for ice formation.

Treatment. Anti-icing will help prevent the formation of ice; deicing will eliminate ice; and abrasives will improve friction between the foot or tire and the surface.

Proper stockpiling. Stockpile snow such that the piles do not encumber driver sight lines or create melt-refreeze slipping hazards to pedestrians; do not pile snow at the end of parking drive aisles; do not pile snow uphill of known and foreseeable pedestrian ways.

Stop creep
. Plow, cut and bank so as to prevent standing snow from creeping into parking stalls, which leads to parked cars further out into the drive aisles and effectively eliminates pedestrian paths at the edges of the drive aisles.

Lighting. The sun is low, and it gets dark early in the winter, thus visibility is dependent on installed lighting. Alert your property manager to replace burned-out bulbs and ask them to keep the lights on. Do not stockpile snow in areas in close proximity to light, which can create shadows across the walking/driving surfaces.

Traffic control. During known peak hours of use, consider placing traffic cones to delineate directional drive aisles, as well as designated pedestrian ways.

This article covered the three most common risks in parking lots during the wintertime. However, additional factors compound wintertime risks in parking lots, from human factors in an aging population to crazy Black Friday deals. Furthermore, the likelihood and severity of those risks will vary based on the functional characteristics of the lot, including the occupancies served, parking lot configurations and times of use. The risk management methodology remains the same: Identify the risks, assess the risks and implement mitigating actions with a focus on reducing the likelihood and severity of those risks.

George Melchior, ASM, is a registered architect and professional engineer and owns GVM Consulting, based in Portsmouth, NH. Contact him at
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