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TABLE F.1 Carbon Dioxide Emissions by Commuting Mode (tons/year)

Mode

Btu per Passenger Milea

Yearly Energy (MBtu)b

Equivalent Gallons Gasolinec

Amount of Yearly CO2 Emissionsd

Difference from Solo Driving

Solo driving

8,333

41.66

333.3

2.98

Bus

2,121

14.77

118.2

1.06

1.92

Rail

1,935

13.84

110.7

0.99

1.99

Carpool

3,788

18.94

151.5

1.36

1.62

Vanpool

882

8.58

68.6

0.61

2.37

aFor solo drivers, the figure is per vehicle-mile for automobile commuting.

bEnergy use = (Btu per passenger-mile) × (10 miles per commuting trip) × (2 trips per day) × (250 commuting days per year). In addition, for bus, rail, and vanpool modes, it is assumed that commuters drive alone 1 mile (at 8333 Btu/mi) each way per day to get to the transfer point. For rail, energy use for commuter rail is used (rather than the lower energy use for transit rail).

cAssumes that 1 gallon of gasoline = 125,000 Btu (Davis et al., 1989).

d(Gasoline usage) × (19.7 lbs CO2/gal gasoline)/(2200 lb/t).

parking spaces are eliminated, it is assumed that none of the 9 million displaced solo commuters continue to drive alone, and all are divided among the four remaining modes. Where parking spaces are priced to reduce the solo driver mode share to 50 percent, the shares for the remaining modes are proportional to those calculated for elimination of parking spaces. (To account for the remaining solo drivers, the other mode shares add up to 50 percent, rather than 100 percent, of all commuters.) The mode splits for displaced drivers are presented in Table F.2.

These mode splits are then applied to the 9 million solo drivers affected by the parking elimination component and the 27 million solo drivers affected by the parking management component. As shown in Table F.3, the combination of these two measures would produce annual emission reductions of 49 Mt of CO2.

Calculation of Cost-Effectiveness

A parking demand management program of the type described in this appendix would involve several types of costs and savings:

• employees' out-of-pocket costs or savings from the use of alternative transportation modes (a figure that includes fuel savings);

• employers' out-of-pocket operational costs or savings from parking management and provision of transportation alternatives;



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