Effects of Population on Space Supply The effects of urban population on downtown parking space supply are shown in Figure 1. Urbanized areas with the same population generally have about the same amount of parking

space.

Total CBD spaces increase as urban areas get larger, but at a diminishing Downtown parking spaces currently approximate 4,500 when urbanized area population is 100,000 and about 18,000 when this population reaches one million. (These space requirements will probably increase in the future.) The

The spaces per registered vehicle decline as the urban area increases in population. When urbanized area population approximates 100,000, central business district parking spaces approximate 110 per 1,000 registered vehicles. When the urbanized area reaches one million people, there are approximately 40 spaces per registered vehicle. For Los Angeles (with an urbanized area population of six million) there are only 18 spaces per 1,000 registered vehicles.

PARKING SPACES PER SQUARE MILE OF CENTRAL BUSINESS DISTRICT

On a square-mile basis, the number of downtown spaces increases gradually as urban population rises. Parking spaces per square mile of downtown approximate 15,000 for urban populations of 100,000, and 23,000 for urban populations of 500,000. When urbanized areas approach two million, parking spaces per square mile level off at about 30,000.

OFF - STREET PARKING SPACES

lesser per capita supply of downtown parking in larger cities results from several factors. There is less relative per capita CBD trip attraction; public transportation generally carries a greater percentage of people downtown, and high land costs may discourage core area off-street parking developments.

Effects of Population on Facility Type Although curb space dominates the parking supply in smaller cities, it becomes a smaller proportion of the total as urban population rises. (Until recently, most downtown garages were constructed only in larger cities.)

As depicted in Figure 4, urban areas of 100,000 population have approxi

OFF-STREET PARKING SPACES

IN RELATION TO URBANIZED AREA POPULATION

As urban areas increase in size, the number of garage spaces increases at a faster rate than parking lot spaces. Central business districts in urbanized areas of 200,000 or less usually have fewer than 1,000 spaces in parking garages. This number increases substantially as urban areas enlarge; there are about 5,500 garage spaces in urban areas of one million in population. The total off-street spaces averaged 2,800 in urbanized areas of 100,000, 16,000 in areas of one million, and about 28,000 in urbanized areas of two million population.

mately 18 per cent of the total parking supply along curbs, 67 per cent in lots, and 15 per cent in garages. In contrast, when urban population reaches one million, only eight per cent of the total spaces are found along curbs, while 65 per cent are in lots and 27 per cent in garages.

Parking Rates Downtown parking rates also rise as urban population increases thus, they usually are higher in large cities. Illustrative examples of this variation for eight selected cities are shown in Table 1. The first hour of parking costs approximately 30 cents in cities of 300,000 population or less, nearly 40 cents per hour in intermediate-sized cities, and over 50 cents in large cities like Philadelphia.

Average all-day rates vary more widely. They range from 46 cents in Charlotte to $1.10 per day in Philadelphia. They average nearly $2.00 in Chicago and substantially more in New York City. Thus, rates appear highest in transit-oriented cities where parking near major activity centers is often at a premium because of competing land uses.5

5Since choice of travel mode is influenced by comparative cost factors, high all-day parking rates may discourage automobile usage.

SOURCE: Comprehensive parking studies in each urban area.

TABLE 2

PARKING FEE AND TRIP PURPOSE IN THREE CENTRAL
BUSINESS DISTRICTS

SOURCE: Comprehensive parking studies in each urban area.

The fees actually paid by parkers relate to both city size and trip purpose. The larger the city, the higher the fee in all purpose categories. As shown by Table 2, workers paid the highest average parking fee in each of three typical cities. Although shoppers actually paid higher hourly fees, their stay was usually shorter, resulting in lower over-all charges. Similarly, people parking for business purposes paid somewhat lower total fees than shoppers, largely because of short durations; yet they often parked in the most convenient and costly locations.

In all cities, downtown parking rates are highest near core areas, and generally diminish as downtown land-use intensity and assessed valuation decrease (Figure 6). This is because rates commonly reflect locations of major parking facilities as they relate to principal business establishments.

Usage - Total daily CBD parkers increase as urban population gets larger, but at a diminishing rate. A ten-fold increase in population results in a 2.5 increase in daily parkers. As shown in Figure 7, daily parkers approximate 14,000 in urban areas of 100,000 population and 36,000 in urban areas of one million. Philadelphia, with a 1960 urbanized area of about 3.6 million, had approximately 66,000 parkers daily.

Many outlying centers in or near major metropolitan areas also generate high parking demands. Beverly Hills, California (1960 population, 30,817), parks over 40,000 vehicles per day, a number equivalent to that for the downtown district serving a city of one million.

Purpose, Duration, and Walking Distance - The great variety of parkers' trip purposes clearly denote the changing mix of downtown land use in large cities and the influence of regional office functions. As urban population rises, work trips increase in proportion, shopping trips diminish, and other purpose categories remain stable (Figure 8).

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