A double-loaded module is a parking layout with a row of stalls on each side of a single drive aisle. It is the basic building block of most parking lots and garages because one aisle serves two rows.
For 90-degree parking, a typical module is about 60 feet wall to wall: two 18-foot stalls and a 24-foot two-way aisle. Angled parking narrows the aisle and usually makes it one-way. Local codes and the chosen design vehicle set the actual numbers. See parking geometry and parking module.
Why it is efficient
- Aisle area is shared by two rows of stalls, so less pavement per space than a single-loaded module.
- Structural bays can be sized to the module, giving column-free parking. See clear-span construction.
- Repeating modules make layouts and wayfinding predictable.
Choices inside the module
- Angle. 90 degrees fits the most cars and allows two-way traffic; angled stalls are easier to enter but need one-way flow.
- Stall width. Wider stalls improve level of service and reduce door dings at the cost of capacity.
- Compact stalls. Mixing in compact stalls can raise counts on paper. See compact stall.
The Parkonomics view
The double-loaded module is the closest thing parking has to a law of physics. Get it right and the rest of the garage lines up behind it; squeeze it and drivers feel it on every turn.
Related terms: Single-Loaded Module, Parking Module, Parking Geometry, Interlock Dimension, Compact Stall, Level of Service