Separate the Stalls, One Line or Two?


Separate the Stalls, One Line or Two?

Should parking stalls be striped with single lines or double lines? Some parking consultants strongly prefer double striping because they believe it helps parkers center their vehicles between stripes, maximizing the space between vehicles. This minimizes conflicts between door openings of adjacent vehicles.
Intuitively, this makes sense, but since the cost for double striping an 18-foot-long by 8-foot-6-inch wide stall is 2.3 times that for single striping, is it true that proper parking – staying within the lines – actually occurs?
To answer this question, a survey was conducted this year of more than 10,000 parkers at 25 garages in six Colorado cities. Garages surveyed included uses for office, mixed-use, residential, transit, educational, health care, municipal, shopping centers and commercial.
Single-line stall striping is preferred over double-line stall striping (72% vs. 28%). A 90Ā° parking angle (two-way traffic flow) is preferred over angled parking (61.1% vs. 38.9%). An 8-foot-6-inch-wide stall is preferred over other widths (71.0% compared with 26.0% for 9′-0″) 9-foot-wide).
In total, 7.6% of patrons are improperly parked, meaning they are parked outside stall striping lines.
Parkers pay little attention to signage or stall striping that designates spaces for small-car-only or compact spaces. A space was found, so they parked in it.
No compelling reason was found to justify the cost and effort of double-line stall striping.
Comments – Improperly
Parked Vehicles
Of the improperly parked vehicles, about 65% were intentionally misparked.
About 10% were parked across striped spaces to avoid door dings from others parking too closely to a new, specialty, classic, etc. vehicle.
The vast majority of improperly parked vehicles are found at the end of a row of parking where there is extra space by a stair/elevator core or by an island curb. These occurrences are seldom harmful to others and they do not diminish the garage capacity.
Instances of improperly parked vehicles are higher on the top level of the garages. Many times the top level is not full, so parkers are not as motivated to be careful how they park. Improper parking is greatly influenced by old, dull striping paint (hard to see the stripes); by poor lighting (dark, causing diminished visibility); and by dirty, cluttered floor surfaces (lack of care by managers leads to lack of care by parkers).
It was observed that garages with the fewest instances of misparking had rovers who placed preprinted notices under wiper blades informing a patron that they were not properly parked.
General Comments
Regarding Stall Striping
Many building owners and garage management companies budget restriping as an annual maintenance expense. Patrons see the striping as they enter a facility, and clean, bright lines set a favorable tone to the parking experience. Almost all stripes are 4 inches wide. White and yellow are the only colors used in the surveyed garages. Patrons and garage operators believe that yellow stands out better. White gets dirty easier and is harder to see if the garage is not clean or well lighted.
There is no observed advantage to striping dead corners or the triangle at the end of a row of angled spaces. Striping those areas creates opportunities for errors and adds to maintenance effort and cost, all for no apparent benefit.
Areas in front of doors or rooms and turnaround areas in garages with dead ends should have diagonal striping in these No Parking zones.
A turnaround area should be at least as wide as a standard parking stall. One additional foot should be added to the width of the turnaround if it is next to a wall or column. It is not necessary to diagonally stripe out spaces on both sides of a parking module for a turnaround. A turnaround space on one side of the module is sufficient.

Paul Mack is President of Parking Consultants LLC in Colorado.
He can be reached at


A Surprising Result:

It is surprising that poor parking practices were observed to be more prevalent with each of the following:

Double-line striping
This is contrary to the belief that double striping helps parkers center their vehicle better with the parking space.

Angled parking (one-way traffic flow).
Intuitively, it should be easier to park in an angled stall because it is less of a
maneuver. Evidently parkers are willing to back up and straighten their vehicle when parking in two-way traffic-flow spaces.

9-foot-wide stalls
Common sense tells us that a wider stall is more forgiving, does not require as much
driving skill, and is easier to park in than a narrower space. Apparently, patrons see the wider space and assume they have parked between the lines, not checking to verify their alignment.

Article contributed by:
Paul Mack
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