
Source: Adapted from P. Hugill (1995), World Trade since 1431, Baltimore:
The Johns Hopkins University Press, p. 213.
One Hour Commuting According to Different Urban Transportation Modes
There is a relationship between the form and structure of cities
that was shaped by subsequent changes in transportation technology.
One way to to express this relationship is through the commuting
range. The above figure depicts a theoretical urban form which is
the summation of successive transport influences. It assumes a
uniform friction of distance and a uniform capacity of transport
infrastructure.
- Walking. Assuming a willingness to commute for one hour,
a pedestrian walking at 5 km per hour could cross about 5 km. The
space / time relationship of such a commute would be a circle of
roughly 10 km in diameter. This helps explain why prior to motorization, cities
were compact since most of the mobility took place by walking.
- Streetcar. A streetcar, like those operating in the first
half of the 20th century, could travel around 15 km per hour along
fixed lines. In this case, the space / time relationship would be
star shaped to reflect the time spent walking to the streetcar line
that has to be deducted to the total travel time. Therefore, someone
living 15 km away from the city center would need to live next to
the streetcar line to fall within the range of one hour maximum
commuting time.
- Cycling. The bicycle became a mode of mass transportation
in the late 19th and early 20th centuries. With approximately the
same speed of a streetcar, but with no fixed line limitations, the
space / time relationship of commuting by bicycle would be a circle
of 15 km in diameter.
- Driving (no freeways). With a driving speed of about
30 km per hour (taking into account stops, congestion
and parking), an automobile creates a spherical space / time relationship
of about 30 km in diameter.
- Driving (with freeways). Along a freeway, a fixed infrastructure,
the driving speed is doubled to 60 km per hour. The space / time
relationship is then star shaped with 60 km of diameter along its
axis.