Using standard highway signs in your parking lot not only makes sign recognition easier and commands authority, it is now the law. Effective January 16, 2007, the Federal Highway Administration requires roads on private property that are "Open to Public Travel" to use the same sign design, sizes, and reflectivity as the highway signs.
This includes roads within shopping centers, parking lot areas, airports, sports arenas, toll roads and other similar facilities. Any road that is privately owned but where the public is allowed to travel without access restrictions including bike paths and recreational facilities must use the highway sign standards.
Parking lot owners and managers may reduce their exposure to costly lawsuits by updating their signs to the highway sign standards or phase them in as the old signs are replaced. There is a manual of standard sign designs named the MUTCD, (Manual of Uniform Traffic Control Devices). Most sign companies are familiar with the MUTCD or you can find them online.
Beyond the MUTCD, there is little guidance for the number and placement of parking lot signs except logic and common sense. The need for parking lot signs is very much related to the number of parking spaces and the facilities use. A large shopping center with many pedestrians and high vehicle turnover will require more signs than a small business park.
MUTCD signs are available in different sizes and reflectivity. The size of the sign required is related to its viewing distance. A larger sign can be seen from further away. As a rule of thumb, the sign's letter height should be one inch for every 50 feet that it required to be seen from. For example, if the sign needs to be read from 150 feet away, you should have at least a 3-inch letter. Larger is better.
The reflectivity of a sign is how bright it is when headlights shine on it. As light bulbs come in different brightness, 60, 75 and 100 watt bulbs, signals are available in engineer grade, high intensity and diamond grade reflectivity. Diamond grade reflective is the brightest. Traffic signs should be at least high intensity reflective.
Since parking lots are the one place where pedestrians and motorist freely roam, right of way signs are very important for safety. It is safest to place a sign anywhere a potential conflict may occur.
Right of way signs are Stop (R1-1), Yield (R1-2), Keep Right (R4-7), Do Not Enter (R5-1), and Pedestrian Crossing (W11-A2). These types of signs are typically used on the access driveway from the highway, along the building frontage, parking islands and for any ring roads. Any signs that are on the state highway's right of way must be the same size required for that highway. Stop signs on the state right of way are typically 30 inches. Because speed traveled in a parking lot is slower, stop signs can be smaller, typically 24 inches.
Pedestrian crossing signs are found at crosswalks and paths connecting to the building frontage. Bicyclist signs should be treated similar to pedestrian signs.
Speed limit signs should only be used on a ring road and are typically ignored and difficult to enforce against motorist infractions. Speed limits should be on 5 mile increments per MUTCD. In smaller parking lots it is illegally that speed limit signs would be needed because vehicles do not have enough space to travel at high speeds.
As for enabling motorist violations, without parking lots signals are installed as a result of engineering studies and certain criteria are met, enforcement of violations by motorist is impractical. There is also the Model Traffic Ordinance which provides provisions relating to police enforceances of traffic regulations on private property, which in a nutshell, is impractical.
Parking signs make it easier for visitors to know where the right spot to park is. This makes it convenient for them to get from their vehicle to a walkway or the facility. Some facilities will reserve parking spaces for special use, for example, Expectant Mothers, Employee of the Month, Clergy or Doctors. Parking signs are typically 12 "x 18" and should be placed no more than 150 feet apart when placed in series. If attached to a barrier or post the parking signs should be engineer grade reflective.
No Parking signs inform motorist where they can not park. Fire safety dictates that Fire Lane signals are posted along the frontage of a building and near fire hydrants. Other no parking signs are found near loading zones and intersections to provide an unobstructed line of sight for motorist. No truck signs are sometimes used because trucks are large and can obstruct the free movement of vehicles.
Handicap Parking signs are used to design areas reserved for the disabled typically found near the building. The handicap parking sign uses the blue wheelchair symbol on the sign. Each state has different requirements for the size and wording of the sign. Some laws require the space to be van accessible and specify fines for violations. It is best to check with the local zoning office for the requirements as they vary broadly.
Property Management signs are used to design areas or notify of rules and policies of the parking lot. Aisle marker signs placed on light poles help visitors remember where they parked. Not liable for loss or damage of property signs may reduce tort liability of the parking lot owner. No Loitering, No Trespassing, No Soliciting, and No Skateboarding signs are used to express management's policies.