30 November 1998
(5) Grading and Drainage. Figures 2-7 and 2-8 illustrate basic principles for grading and
draining parking lots. Parking lot grades and slope directions are determined utilizing the
drainage requirements established in the surface water management plan prepared for the
project site. Swales should be at a depth of no less than 30.5cm (12 in.). Provide positive
drainage in parking lots and accomplish the following:
(a) Maintain a relatively constant grade across the lot that includes no less than the
minimum slope of one (1) percent required for positive drainage to properly direct drainage to
swales or to drainage inlets.
(b) Provide a maximum slope within a 90-degree parking space of five (5) percent
from front to rear end and one and one-half (1 ) percent from side to side.
(c) Provide a maximum slope within a 45-degree or 60-degree parking space of five
(5) percent from front to rear end and one (1) percent from side to side.
(d) Use islands and medians to accommodate change in elevation between the
access drive and parking areas or between different parking levels.
(e) Provide sheet flow drainage across small, flat parking lots into swales in
surrounding grassed areas that are designed for erosion control.
(f) Control runoff with curbing that directs the runoff to the sides and corners of larger
(more than 100 spaces) and/or steeper lots.
(g) Avoid channeling of sheet flow.
(h) Avoid ponding water.
Avoid creation of an impoundment zone in the center of the lot.
(j) Provide sufficient spot elevations to move water off the lot.
(k) Provide adequate drainage inlets to move water off the lot.
(6) Lighting. Illuminate parking lots with uniform lighting coverage for pedestrian and
vehicular safety and security. TM 5-811-1 provides guidance on lighting parking areas.
(7) Pavement Marking and Signage. The Manual on Uniform Traffic Control Devices for
Streets and Highways (ANSI D 6.1e) provides guidance on pavement marking and signage.
c. Parking Structures. Parking structures are to be designed as structures with the design
vehicle applied as described above.
2-5. PETROLEUM, OIL AND LUBRICATION (POL) PARKING AREAS. MIL-HDBK-1022
provides design criteria for facilities, which may support fueling activities. These facilities include
operations buildings, contaminated fuel recovery systems, roads, utilities, and parking areas.
2-6. SPECIAL CIRCULATION AREAS. Circulation areas for other than normal passenger car
traffic have special requirements to meet traffic safety. These areas require additional space to
accommodate unusual traffic patterns and to provide greater turning radii, for maneuverability.