Parking and Loading Requirements
Summary
Zoning requires a minimum number of off-street parking spaces for each use, expressed as a ratio to units, floor area, or seats, and loading spaces sized for delivery trucks. Parking requirements drive site area, structure cost, and the building footprint, and they are changing quickly as cities reduce or remove minimums.
Cols
Scope
- Parking ratios, reductions, and loading standards are set by each local ordinance and are changing by state law. Always verify the municipal code's definitions and the current zoning for the project parcel
- Covers how requirements are expressed, common reductions, reform trends, and typical loading space dimensions
- Accessible parking counts and sizes follow the accessibility standards and are in the accessibility notes
Terminology
- Parking minimum: the least number of off-street spaces a development must provide, set in the zoning ordinance
- Parking maximum: a cap on the number of spaces a development may provide
- Parking ratio: the requirement per unit of use, such as spaces per dwelling unit or per 1,000 sq ft
- Shared parking: one set of spaces serving uses with different peak times
- Parking demand: the number of spaces a use actually fills at its peak
- Off-street parking: parking on the lot or an approved nearby lot rather than on the street
- Loading berth (space): a space for trucks to load and unload, off the street
- Vertical clearance: the height clear of overhead obstructions in a loading berth
- ITE Parking Generation: a traffic engineering reference that supplies observed parking data
- Parking reform: reduction or elimination of minimums, often paired with maximums
Requirements
How minimums are expressed
- Requirements vary by use. Examples from the literature and municipal codes: residential about one space per apartment; retail about one space per 300 sq ft; restaurants about one space per 100 sq ft of dining area; hospitals two spaces per bed; churches one space per five pew seats
- Many cities base ratios on observed peak demand data such as ITE Parking Generation, which gives data rather than prescribed minimums
- Ratios changed over time: residential spaces per unit rose from 0.8 in 1950 to a peak of 1.7 in 1998 and fell to 1.1 by 2022; office spaces per 1,000 sq ft rose from 1.25 in 1950 to 3.75 in 1999 and fell to 2.25 by 2022
Reductions and reform
- Common reductions: shared parking, nearby transit, bicycle parking, car-share spaces, and small units
- More than 35 major cities have reduced or eliminated minimums since 2015, and several states (Oregon, California, Colorado, Washington, Connecticut, and Illinois) have laws limiting them
- One state law caps minimums at 0.5 spaces per dwelling unit and two spaces per 1,000 sq ft of commercial space
- Some jurisdictions pair repeal with maximums that cap the parking a developer may build
Loading
- A loading space commonly measures at least 12 ft wide and 35 ft long, outside aisles and maneuvering space, with a vertical clearance of at least 14 ft
- Other codes use 40 ft long and 15 ft clearance, 50 ft long for larger buildings, or lengths of 35 ft or 65 ft depending on the truck
- The number of berths follows a schedule by gross floor area. One tiered schedule: 5,000 to 10,000 sq ft, one berth of 10 ft by 35 ft; 10,001 to 25,000, two berths; 25,001 to 40,000, two berths of 12 ft by 50 ft; 40,001 to 100,000, three berths of 12 ft by 50 ft with 14 ft clearance
- Loading spaces are on the same lot as the building, do not project into a public right-of-way, and are not in a front yard
- Access is from a street at least 15 ft wide, with durable all-weather surfacing and drainage
Worked examples
Parking count
An illustrative ordinance: apartments 1 space per unit, retail 1 space per 300 sq ft, restaurant 1 space per 100 sq ft of dining area.
| Use | Quantity | Calculation | Spaces |
|---|---|---|---|
| Apartments | 24 units | 24 × 1 | 24 |
| Retail | 12,000 sq ft | 12,000 ÷ 300 | 40 |
| Restaurant | 2,000 sq ft dining | 2,000 ÷ 100 | 20 |
| Total, before reductions | 24 + 40 + 20 | 84 |
A 25 percent shared-parking reduction on the commercial spaces would lower the commercial 60 to 45, total 69. A state law capping apartments at 0.5 per unit would lower the residential 24 to 12.
Loading berths
A 30,000 sq ft retail building under the tiered schedule above.
| Step | Check | Result |
|---|---|---|
| Floor area tier | 25,001 to 40,000 sq ft | Two berths |
| Berth size | 12 ft by 50 ft each | Total 1,200 sq ft of berth area |
| Clearance | 14 ft | Required where enclosed or covered |
| Location | Same lot, not in a front yard, not in the right-of-way | Place at the rear or side |
Site area effect
| Item | Calculation | Result |
|---|---|---|
| Surface parking stall and aisle | About 300 to 350 sq ft per space (assumed) | 84 spaces × 325 = 27,300 sq ft |
| Effect | Parking competes with building footprint and landscaping | Consider structured or shared parking |
Coordination
- Civil and landscape: parking layout drives site area, grading, stormwater, and the interior island landscaping requirements
- Accessibility: accessible spaces count toward the total; coordinate with the accessible parking note
- Electric vehicles: EV-ready space requirements may be set by the ordinance or building code
- Bicycle parking: often required and can replace some car spaces
- Traffic and transportation staff: shared parking and reductions need studies
- Delivery operations: confirm the truck size and the turning movements with the owner and a traffic consultant
Common issues
- Applying the wrong ratio: uses and floor area definitions differ (gross, net, dining area)
- Not applying reductions: shared parking and transit credits need an application
- Loading on the street: loading in the right-of-way or front yard is usually prohibited
- Truck size mismatch: a 35 ft berth does not fit larger trucks
- Law changes: state reform laws may supersede a local minimum; check current law
- Structured parking: garages count toward floor area and height in some ordinances
Standards
- ITE Parking Generation: observed parking demand data
- Local zoning ordinance: parking tables and loading schedules
Sources
- Wikipedia: Parking minimum, https://en.wikipedia.org/wiki/Parking_minimum
- City of Baltimore: design of off-street loading spaces, https://codes.baltimorecity.gov/us/md/cities/baltimore/code/32/16-901
- Town of Vail: off-street parking and loading, https://codelibrary.amlegal.com/codes/vailco/latest/vail_co/0-0-0-10909
- Village of Worth, IL: off-street parking and loading, https://codelibrary.amlegal.com/codes/worthil/latest/worth_il/0-0-0-4698