Civil Engineering Reference
In-Depth Information
23.2.3.1 Transit Supportive Densities
Several studies have suggested minimum household densities necessary to support
transit service. Pushkarev and Zupan [
6
] have suggested typical minimum gross
residential density of approximately 4 units per gross acre for hourly transit service.
Higher residential densities are needed for more frequent service. Table
23.4
gives the gross residential densities and downtown development densities suggested
by Pushkarev and Zupan to support various public transport modes [
7
].
Table 23.4 Transit modes related to residential density
Mode
Service
Minimum necessary
residential density
Dwelling units per
acre
Remarks
Dial-a-bus
Many origins to
many destinations
6
Only if labor cost are not more than
twice those of taxis
Dial-a-bus
Fixed destination or
subscription service
3.5
-
5
Lower figure if labor costs twice
those of taxis: higher if thrice those
of taxis
Local bus
“
minimum
”
1/2
mile route
spacing,40 buses
per day
4
Local bus
“
1/2
mile route spacing,
20 buses per day
Intermediate
”
7
Average, varies as a function of a
downtown size and distance from
residential area to downtown
“
Frequent
”
1/2 mile
route spacing, 120
buses per day
Local bus
15
Express
bus
—
reached
on foot
Five buses during
2 h peak period
15 Average density
over 2 mi
2
From 10
-
15 miles away to largest
downtowns only
tributary
area
Express bus
—
reached by
auto
5
−
10 buses during
2 h peak period
3 Average density
over 20 mi
2
From 10 to 20 miles away to
downtowns larger than 20 million
ft
2
of nonresidential floor place
tributary
area
To downtowns 20
-
50 million ft
2
of
nonresidential floor place
Light rail
5 min headway or
better during peak
hour
9 Average density for
a corridor of
25
-
100 mi
2
Rapid transit
5 min headways or
better during peak
hour
12 Average density for
a corridor of
100
To downtowns larger than
50 million ft
2
of nonresidential
fl
150 mi
2
floor place
-
20 trains a day 1
-
2 Only the largest downtowns, if rail
line exists
(
Source
Reference [
7
]). Courtesy of Indiana University Press, Bloomington. All rights reserved
Commuter
rail
