The following excerpt was taken from the1992 edition of the Transportation
Planning Handbook, published by the Institute of Transportation Engineers (p. 177).
Looking at CBDs in general, the following relationships are typical:
- On-street (curb) parking is related to city population, typically decreasing to about 10
percent of total supply in cities over 250,000 population.
- The demand for long-term, work purpose parking increases with population size, ranging
from 20 percent of total parkers for cities under 100,000 to over 30 percent for cities
approaching 1 million or more population.
- The average walking distance increases with city size.
- The parking duration varies by trip purpose and population size. Work trip and
residential parking exhibit the longest durations, while durations for all trip purposes
increase with city size.
- The parking turnover at the curb is usually three to four times greater than for
off-street spaces. At all facilities, turnover is influenced by the type of parker, the
rate structure, local regulations, and enforcement levels. Furthermore, larger cities
generally experience lower parking turnover than smaller cities.
- Parking accumulation peaks between 11:00 A.M. and 2:00 P.M. in the average CBD; however,
different trip purposes exhibit unique accumulation patterns. The peak accumulation seldom
exceeds 85 percent of the total parking supply, even though parts of the area are severely
deficient in parking supply (location is the key factor). Peak accumulation tends
to increase with population size, but at a diminishing rate.