Trip Reduction Tables
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TDM Encyclopedia
Victoria Transport Policy Institute
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Updated
March 8, 2007
This chapter contains tables indicating the reduction in commute trips that can be expected from various combinations of Commuter Financial Incentives, such as increased parking and road charges, and financial benefits to those who use alternative modes. The Transport Elasticities chapter provides additional information on the travel impacts of various price changes.
The tables below indicate the reduction in commute trips that can be expected from various combinations of parking charges and financial benefits for alternative modes, based on a commonly used reference document published by Institute of Transportation Engineers and the U.S. Department of Transportation (Comsis, 1993, Table 3.3-8), updated to reflect 30% inflation between 1993 and 2000.
These tables take into account variations in worksite settings, including its location (suburban, activity center, central business district), and whether carpooling or transit are favored as alternative modes. For example, Table 3 indicates that a $1.30 per day rideshare and transit subsidy provided to employees at a transit-oriented activity center where parking costs $2.60 per day is likely to result in a 43.6% reduction in commute trips, while in a rideshare-oriented Central Business District, a $2.60 per day rideshare and transit subsidy matched with a $4.00 per day parking fee would only cause a 33.5% trip reduction compared with free parking and no subsidy for alternative modes.
These tables use three geographic categories:
· Rideshare Oriented refers to locations where
ridesharing (carpools and vanpools) provides more than half of all commute
travel by alternative modes.
· Mode Neutral refers to locations where
ridesharing and transit represent about the same portion of alternative commute
travel.
· Transit Oriented refers to locations where
transit provides more than half of all commute travel by alternative modes.
The table below indicates the typical mode split for these locations without Commuter Financial Incentives (i.e., free parking and no subsidies for transit or ridesharing). Two indicators are used to measure the effectiveness of trip reduction efforts:
·
Average Vehicle Occupancy is calculated by dividing the number of persons
traveling in private vehicles (but not transit) by the number of private
vehicle trips.
·
Average Vehicle Ridership is calculated by dividing the number of persons
traveling by all person trips (including transit riders) by the number of
private vehicle trips.
Table 1 Typical Mode
|
|
Low Density Suburb |
|
Regional CBD/Corridor |
|
Single Occupant Vehicle |
85% |
66% |
41% |
|
Transit |
7% |
16% |
30% |
|
Rideshare |
8% |
18% |
29% |
|
Average Vehicle Occupancy |
1.05 |
1.20 |
1.35 |
|
Average Vehicle
Ridership |
1.13 |
1.35 |
1.90 |
CBD = Central Business
District
The tables below show the percentage reduction in automobile trips that Commuter Financial Incentives typically cause under various geographic conditions.
Table 2 Rideshare/Transit Subsidy = $0
|
Worksite Setting |
Daily Parking Charge (2000 U.S) |
||||
|
|
$0 |
$1.30 |
$2.60 |
$4.00 |
$5.20 |
|
Low density suburb, rideshare oriented |
0.0 |
5.9 |
13.1 |
21.0 |
28.6 |
|
Low density suburb, mode neutral |
0.0 |
6.5 |
15.1 |
25.3 |
36.1 |
|
Low density suburb, transit oriented |
0.0 |
6.7 |
15.7 |
26.7 |
38.8 |
|
Activity center, rideshare oriented |
0.0 |
10.8 |
21.4 |
30.7 |
37.9 |
|
Activity center, mode neutral |
0.0 |
12.3 |
25.1 |
37.0 |
46.8 |
|
Activity center, transit oriented |
0.0 |
14.3 |
30.5 |
46.8 |
61.4 |
|
Regional CBD/Corridor, rideshare oriented |
0.0 |
12.4 |
21.7 |
28.2 |
32.5 |
|
Regional CBD/Corridor, mode neutral |
0.0 |
17.5 |
31.8 |
42.6 |
50.0 |
|
Regional CBD/Corridor, transit oriented |
0.0 |
22.5 |
42.6 |
58.7 |
70.6 |
Values
in the table indicate the percentage reduction in commute trips compared with
no fees or subsidies.
Table 3 Rideshare/Transit Subsidy = $1.30
|
Worksite Setting |
Daily Parking Charge (2000 U.S) |
||||
|
|
$0 |
$1.30 |
$2.60 |
$4.00 |
$5.20 |
|
Low density suburb, rideshare oriented |
5.8 |
13.0 |
20.9 |
28.5 |
35.0 |
|
Low density suburb, mode neutral |
5.6 |
13.9 |
23.8 |
34.4 |
44.5 |
|
Low density suburb, transit oriented |
5.5 |
14.1 |
24.8 |
36.6 |
48.3 |
|
Activity center, rideshare oriented |
10.2 |
20.8 |
30.0 |
37.2 |
42.4 |
|
Activity center, mode neutral |
10.5 |
23.1 |
34.9 |
44.8 |
52.2 |
|
Activity center, transit oriented |
11.3 |
27.2 |
43.6 |
58.6 |
70.9 |
|
Regional CBD/Corridor, rideshare oriented |
11.3 |
20.6 |
27.2 |
31.6 |
34.4 |
|
Regional CBD/Corridor, mode neutral |
14.5 |
29.1 |
40.0 |
47.7 |
52.8 |
|
Regional CBD/Corridor, transit oriented |
18.1 |
38.8 |
55.6 |
68.2 |
76.9 |
Values
in the table indicate the percentage reduction in commute trips compared with
no fees or subsidies.
Table 4 Rideshare/Transit Subsidy = $2.60
|
Worksite Setting |
Daily Parking Charge (2000 U.S) |
||||
|
|
$0 |
$1.30 |
$2.60 |
$4.00 |
$5.20 |
|
Low density suburb, rideshare oriented |
13.0 |
20.8 |
28.4 |
34.9 |
40.0 |
|
Low density suburb, mode neutral |
12.7 |
22.4 |
32.8 |
42.9 |
51.5 |
|
Low density suburb, transit oriented |
12.6 |
22.9 |
34.5 |
46.1 |
56.5 |
|
Activity center, rideshare oriented |
20.1 |
29.3 |
36.6 |
41.8 |
45.5 |
|
Activity center, mode neutral |
21.2 |
33.0 |
42.9 |
50.4 |
55.8 |
|
Activity center, transit oriented |
24.0 |
40.5 |
55.8 |
68.6 |
78.3 |
|
Regional CBD/Corridor, rideshare oriented |
19.6 |
26.2 |
30.6 |
33.5 |
35.3 |
|
Regional CBD/Corridor, mode neutral |
26.3 |
37.5 |
45.4 |
50.7 |
54.1 |
|
Regional CBD/Corridor, transit oriented |
34.8 |
52.3 |
65.6 |
74.9 |
81.1 |
Values
in the table indicate the percentage reduction in commute trips compared with
no fees or subsidies.
Table 5 Rideshare/Transit Subsidy = $4.00
|
Worksite Setting |
Daily Parking Charge (2000 U.S) |
||||
|
|
$0 |
$1.30 |
$2.60 |
$4.00 |
$5.20 |
|
Low density suburb, rideshare oriented |
20.7 |
28.3 |
34.8 |
39.9 |
43.5 |
|
Low density suburb, mode neutral |
21.0 |
31.3 |
41.3 |
49.9 |
56.6 |
|
Low density suburb, transit oriented |
21.1 |
32.5 |
44.0 |
44.0 |
62.8 |