Transportation Planning

In this chapter we consider transportation planning as practiced at the municipal and metropolitan levels. Before we begin, some background on transportation trends since World War II will be useful.


In 1945, the last year of World War II, the United States had a population of 133 million people who owned 25 million automobiles. By 2009 the U.S. population had grown to 304 million, a factor of about 2.3. Automobile registrations had grown to 135 million, a factor of 5.5. But that figure greatly understates the growth of privately owned automotive transportation, for sport-utility vehicles (SUVs) and vans are classified as light trucks and counted separately. In 2008 there were approximately 100 million vehicles described as "two axle four tired trucks," which effectively means SUVs, vans, and pickups, a very large percentage of which are used for personal transportation.1

One powerful force behind the increase in automobile ownership was the large increase in average real personal income in the years following World War II. Not only did the general prosperity enable more people to own automobiles, but that same prosperity also facilitated a great wave of suburbanization. The postwar suburbanization and the increase in automobile ownership were complementary phenomena. Widespread automobile ownership facilitates suburbanization. On the other hand, moving from the central city to the suburbs increases one's need for an automobile.

Table 12-1 shows the nation's overwhelming reliance on the automobile for commuting to work. Note the relative stability in the picture over the 19 years covered by the table. Table 12-1 actually understates the reliance on the automobile versus public transportation for all travel because public transportation competes best with the automobile in the journey to work. Driving is often least convenient during the morning and evening rush, and getting to work has an element of necessity that many other trips lack.

Public transportation usage peaked in the last year of World War II. Gasoline was rationed and production of automobiles had been suspended for several years. From 19 billion trips by fare-paying passengers in 1945, the total declined to a postwar low of 5.6 billion in 1975. By 2009 that figure had risen to 10.4 billion, in part because of heavy federal investment in public transportation over the last three decades and partly because of increases in the price of gasoline.2 Despite this increase, transit still constituted a smaller percentage of all trips in 2009 than it had in 1975.

Public transportation usage is distributed very unevenly in the United States. Of the 10.4 billion total annual trips, 3.2 billion—almost 31 percent— are provided by a single agency, the Metropolitan Transportation Authority (MTA), which covers New York City and the New York State portion of the New York metropolitan area. Chicago is second at just over half a billion trips a year, and Los Angeles is third at just under half a billion. For much of the nation public transportation is minimal. Subway (heavy rail) transportation is even more unevenly distributed. A single system, the New York City subway, accounts for 2.4 billion trips per year, over two-thirds of the national total.3

The decline in public transportation is not hard to explain. Increased automobile ownership eliminated millions of potential transit customers. Suburbanization meant the movement of millions of households into areas where, because of reduced congestion, the automobile works better than in central cities. Conversely, the dispersed suburban land-use pattern makes the provision of public transportation, which depends on high volumes on fixed routes, more difficult. The spreading out of residences and workplaces with the process of suburbanization complicates both the collection (getting the rider to the public transit vehicle) and the distribution (getting the rider from the vehicle to his or her final destination) problems.

Public transportation is also bedeviled by the trade-off between the spacing of stops and average speed. The more closely spaced the stops are, the lower is the average speed. But increasing the distance between stops makes the collection and distribution problems more severe. Because of the need for frequent stops, public transportation tends to be slow. In 2009 the average speed for all public transportation vehicles in the United States was 14.9 miles per hour (mph). Buses averaged 12.5 mph and commuter rail with its less frequent stops and its own right-of-way averaged 31.2 mph.4

These figures, which do not include waiting times, have not changed appreciably for many years, nor can they readily be changed; minimum loading times and the maximum acceleration and deceleration rates that are acceptable are not a matter of what technology is capable of, but rather what is safe and comfortable for passengers.

The ideal environment for public transportation is seen in a number of the large, older, eastern cities—with masses of jobs concentrated in the urban core and masses of apartments concentrated near transit stops. This arrangement simplifies the collection and distribution problems and provides a large enough market to sustain frequent service. The high densities also make automobile usage less attractive. But that pattern of development is very much the opposite of the dominant land-use trends since World War II. Transportation to work is emphasized here because it is the mainstay of public transportation demand. When public transportation use declines, it is generally the journey to work that holds up best. Trips for shopping, recreation, and the like fall off more rapidly.

Measured in percentage terms, the biggest growth area in transit has been in para-transit, also referred to as demand response systems. These systems, with names like Dial-a-Ride, send a vehicle in response to a call. They do not operate on fixed routes or have a fixed schedule. Such systems may

TABLE 12-1 Transportation to Work in 1990, and 2000, and 2009 (figures in millions)


Persons in 1990

Persons in 2000

Persons in 2009

All modes




Car, truck, or van




Drove alone




Public transportation








Subway or elevated








Selected other





Work at home




Ride bicycle




Note: Comparable figures from the 2010 census are not available at this writing. Given that there has not been a very large change in public transportation usage over the last decade it is unlikely that they will be very different.

Sources: 1990 Census of the Population, Social and Economic Characteristics, Table 18; and 2000 census, Summary File 3 (SF 3), Table P30, U.S. Bureau of the Census, Department of Commerce. American Community Survey, Bureau of the Census, Commuting in the United States, U.S. Bureau of the Census, Table 1. The Bureau of the Census stopped including commuting data in the decennial census after 2000.

serve a specialized population such as individuals who are disabled or elderly, or they may service an area in which it is not economically feasible to provide scheduled, fixed route public transportation. In that sense, these systems are a kind of publicly supported taxi service to serve those with few other transportation choices.

From 2004 to 2012 transit use in the United States increased by 15 percent. Some of that increase is from new systems coming on line, but most is probably from more intense use of pre-existing facilities. U.S. auto use peaked in 2007, and from then to 2012 declined by 3 percent. Whether or not these figures indicate the beginning of a turning point in long-term trends or just the effect of the Great Recession beginning in 2008 remains to be seen.

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