Entrance Considerations
The first maneuver that a parking vehicle will make involves leaving the street and
entering the off-street parking lot. This maneuver, while simple, requires some careful
thought by the parking lot designer.
Analysis of the demand for parking may indicate that there are periods during the day
in which a large number of vehicles want to enter the parking facility at roughly the same
time. The entrance to the parking lot must be able to handle the entering traffic without
forcing vehicles to wait in the street, because stagnant vehicles will reduce the capacity
of the adjacent street. To avoid conflicts with other traffic, entrances should be located
as far from intersections and conflict points as possible. Multiple entrances may ease
access and reduce restriction on the adjacent roadways.
Years of experience have produced general entrance dimensions that seem to work. The
basic nominal design width for a two-way driveway serving commercial land use is 30 ft.,
with 15 feet radii. With greater volumes such as at a shopping center, a 36-ft driveway
may be appropriate. It should be marked with two exit lanes (each 10 or 11 ft wide) and a
single entry lane (14-16 ft wide) to accommodate the off-tracking path of entering
vehicles. Larger commercial facilities such as regional shopping centers may require twin
entry and exit lanes separated by a 4-12 foot median.
Many areas of the country have specific regulations or guidelines for the design of
access facilities. It is important that the local and state regulations concerning access
management are followed when designing access to off-street parking facilities.
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