Civil Engineering Reference
In-Depth Information
Fig. 3.1 The spreading of traf
c congestion
another disparate element into the traf
icts and congestion.
The street cars often operated at very close spacing and often congested each other.
c stream, adding con
fl
In 1891, on Tremont Street in Boston:
during the afternoon rush hour, cars
were packed so close together that one could walk from Scully Square to
Boylston Street on the car roofs
“
”
[
3
].
In Philadelphia, street cars, horse drawn vehicles comingled and nothing moved
(Fig.
3.2
).
In Chicago, Dearborn Street and Randolph Street experienced gridlock condi-
tions as a result of rush hours vehicle-vehicle and vehicle-pedestrian con
icts
(Fig.
3.3
). Street cars and horse-drawn vehicles were major contributors to
congestion.
fl
In Tokyo
c congestion
experienced in 1924, caused by the demand volume of vehicles and pedestrians
approaching a bridge with insuf
'
s Honjo Quarter, Fig.
3.4
shows the intensity of traf
cient capacity.
c control
and management. This led to both chaotic confusion and congestion in many
business centers. Figure
3.5
shows the situation in downtown Los Angeles during
the mid 1920s.
These conditions led many cities to (1) establish traf
The growth of motorization in the 1920s often preceded effective traf
c regulations and controls,
(2) remove produce markets from central cities, and (3) increase the width of
streets. Chicago, for example, relocated the South Water Market, built two-level
Michigan Avenue and Wacker Drive, (4) banned left turns in the
and (5)
signalized downtown intersections. Other cities also began to manage their traf
“
Loop,
”
c,
and the field of Traffic Engineering emerged.
The 1930s and 1940s were characterized by continued growth in automobile
traf
c congestion on radial highways leading to or within the city center. Figure
3.6
shows congestion patterns in Chicago and its environs in 1942.
Traf
c backups were common on many city streets, in some cases extending for
miles. Figure
3.7
shows 1940 rush hour congestion on Gratiot Avenue, a major
arterial in Detroit.
