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How much can vehicle travel be reduced inCalifornia through land use policies?
David R. Heres
Postdoctoral Researcher
2010 Behavior, Energy & Climate Change ConferenceSacramento, November 17
Transportation GHG mitigation strategies towardsCalifornia’s 2020 target
Regional transportation GHG targets are ranked third among themitigation strategies within the transportation sector.
1. Vehicle GHG standards (18.8%)
2. Low carbon fuel standard (9.5%)
3. Regional transportation GHG targets (2%)
Measures being considered by MPOs to achieve theregional reduction targets
I Extend bicycle networksI Increase high occupancy lanesI Improve the extension and service of transitI Incentivize telecommutingI Promote the use of alternative modes of transportation and
travel reductionI Promote compact development - high density with mix of
land uses
Contrasting types of housing development
Average residential density in the city of San Francisco is almosttwice that from Los Angeles and 6 times that from a typicalCalifornian suburb.
Mean daily VMT per HH for different residential density,business-housing ratio, and transit density classes
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17
19
21
23
25
27
29
31
33
35
1 2 3 4 5 6 7 8 9 10
MeanHHDailyVMT
Class
Residen2alDensity Mix "TransitDensity"
Previous estimates for VMT reductions responding toincreases in residential density in California
I CEC(2007): 20% to 40% VMT reduction
I Rodier (2008): 4% reduction in VMT in a 10-year horizon.Based on studies assessing the impacts of land-use changesand transit improvements
I Fang (2008): 3% VMT reduction in response to a doubling inresidential density
I Brownstone and Golob (2009): 12% VMT reduction inresponse to a doubling in residential density
Previous estimates for VMT reductions responding toincreases in residential density in California
I CEC(2007): 20% to 40% VMT reductionI Rodier (2008): 4% reduction in VMT in a 10-year horizon.
Based on studies assessing the impacts of land-use changesand transit improvements
I Fang (2008): 3% VMT reduction in response to a doubling inresidential density
I Brownstone and Golob (2009): 12% VMT reduction inresponse to a doubling in residential density
Previous estimates for VMT reductions responding toincreases in residential density in California
I CEC(2007): 20% to 40% VMT reductionI Rodier (2008): 4% reduction in VMT in a 10-year horizon.
Based on studies assessing the impacts of land-use changesand transit improvements
I Fang (2008): 3% VMT reduction in response to a doubling inresidential density
I Brownstone and Golob (2009): 12% VMT reduction inresponse to a doubling in residential density
Previous estimates for VMT reductions responding toincreases in residential density in California
I CEC(2007): 20% to 40% VMT reductionI Rodier (2008): 4% reduction in VMT in a 10-year horizon.
Based on studies assessing the impacts of land-use changesand transit improvements
I Fang (2008): 3% VMT reduction in response to a doubling inresidential density
I Brownstone and Golob (2009): 12% VMT reduction inresponse to a doubling in residential density
Non-linearity
Frequency distribution of HH daily VMT0
001000
1000
1000200020
0020003000
3000
3000400040
004000Frequency
Freq
uenc
yFrequency0
0
0100
100
100200
200
200300
300
300400
400
400500
500
500VMT
VMT
VMT
Residential self-selection
Residential self-selection
Elasticities for different specifications of the Modified TwoPart Model with Instrumental Variables
Dependent variable: Vehicle miles traveled(1) (2) (3) (4) (5) (6) (7)
residential density -0.1898* - -0.1934* -0.1399* - -0.1622* -
business-housing ratio - -0.4442* 0.0524 - -0.2118 0.1486 -
transit density - - - -0.08611 -0.1476* -0.0814 -0.1569*
Are IVs’ relevant? Yes Yes Yes Yes Yes Yes -Are IVs’ valid? Yes No Yes Yes No Yes -
Other control variables: age of older member in the HH, % of HH members that work , HH size, number of vehicles in theHH, indicator variables for income class, urban area, and region.Instrumental variables (IVs): % of housing units built before 1940, % of HHs where head’s race is other than white, % offamily HHs (all measured for the census tract where the HH is located)
Required increases on two alternative policies to achievea reduction of 4% in VMT
Median LO UPResidential density increase 24.6% 20.7% 28.6%Gasoline price increase 20.1% 13.6% 26.7%
Trajectory of the price of gasoline
100
150
200
250
300
350
400
450
500
Jan01
,200
7
Mar01,200
7
May01,200
7
Jul01,200
7
Sep01
,200
7
Nov01,200
7
Jan01
,200
8
Mar01,200
8
May01,200
8
Jul01,200
8
Sep01
,200
8
Nov01,200
8
Jan01
,200
9
Mar01,200
9
May01,200
9
centspe
rgallo
nofgasolineinCalifo
rnia
64%increase
62%decrease
73%increase
Conclusions
I Results from this study imply that, everything else equal,doubling residential density would reduce VMT by roughly20%
I The estimates indicate that the 4% reduction in VMT toachieve the GHG reductions from land-use policies inCalifornia would require increasing residential density byalmost 25%.
I On the other hand, estimates from studies looking at the effectof price variations on travel demand imply that a 20% increaseon top of the price of gasoline would suffice to reduce travelby those same amounts
I A combination of pricing and land use policies may deliver thebest results. However, political opposition and technicalconstraints, among other obstacles, will likely hinder timelyimplementation of either policy
Conclusions
I Results from this study imply that, everything else equal,doubling residential density would reduce VMT by roughly20%
I The estimates indicate that the 4% reduction in VMT toachieve the GHG reductions from land-use policies inCalifornia would require increasing residential density byalmost 25%.
I On the other hand, estimates from studies looking at the effectof price variations on travel demand imply that a 20% increaseon top of the price of gasoline would suffice to reduce travelby those same amounts
I A combination of pricing and land use policies may deliver thebest results. However, political opposition and technicalconstraints, among other obstacles, will likely hinder timelyimplementation of either policy
Conclusions
I Results from this study imply that, everything else equal,doubling residential density would reduce VMT by roughly20%
I The estimates indicate that the 4% reduction in VMT toachieve the GHG reductions from land-use policies inCalifornia would require increasing residential density byalmost 25%.
I On the other hand, estimates from studies looking at the effectof price variations on travel demand imply that a 20% increaseon top of the price of gasoline would suffice to reduce travelby those same amounts
I A combination of pricing and land use policies may deliver thebest results. However, political opposition and technicalconstraints, among other obstacles, will likely hinder timelyimplementation of either policy
Conclusions
I Results from this study imply that, everything else equal,doubling residential density would reduce VMT by roughly20%
I The estimates indicate that the 4% reduction in VMT toachieve the GHG reductions from land-use policies inCalifornia would require increasing residential density byalmost 25%.
I On the other hand, estimates from studies looking at the effectof price variations on travel demand imply that a 20% increaseon top of the price of gasoline would suffice to reduce travelby those same amounts
I A combination of pricing and land use policies may deliver thebest results. However, political opposition and technicalconstraints, among other obstacles, will likely hinder timelyimplementation of either policy
Thank you
David R. HeresBasque Centre for Climate ChangeBilbao, Bizkaia, [email protected]
Further reading: Heres & Niemeier (2011) in TransportationResearch Part B, 45(1): 150-161