The study found that an integrated set of land-use-related transportation
strategies would achieve a cumulative reduction in GHG emissions of 0.3% to 2.1%,
relative to the study’s baseline and depending on the deployment level.
That rate of reduction puts such strategies somewhere in the
middle of the mix. Pricing strategies (e.g., pay-as-you-drive insurance,
vehicle-miles-traveled fees, and congestion pricing) would reduce GHG emissions
more effectively, whereas highway-capacity expansion and bottleneck relief
would increase GHG emissions over the
40-year period.
Strategies were modeled in bundles to assess their
synergistic effects on GHG emissions. This analysis found that land-use-related
transportation strategies and expanded transit services combined were more
effective than either of those strategies alone. In fact, these two strategies
combined could achieve “meaningful” GHG emissions reductions by 2050, even if
the more effective economy-wide pricing strategies were not implemented, the study found. This approach could avoid
the inequities of pricing strategies, which were found to be disproportionately
burdensome for low-income households; however, the expansion of transit
services would be costly.
The study didn’t model the emissions-reduction potential of
specific land-use-related transportation strategies, but instead considered
such strategies as compact neighborhoods, reuse of infill sites, and
higher-density development near rail stations and bus corridors.
The GHG reduction benefits would “accrue slowly in the short
term” and then begin to “escalate significantly in the later years,” the study
says. The delay is due to the long timeframe required to implement land-use strategies
and the high need for participation and acceptance by multiple stakeholders,
the report suggests.
Statistical modeling of these strategies is important
because, as the report notes, “transportation contributes roughly 28% of the United States’
total GHG emissions—and transportation emissions have been growing faster than
those of other sectors.”
The report aims to guide policymakers, transportation
planners and researchers who study and chart climate-change initiatives and
policies. The research was sponsored by the Urban
Land Institute and other organizations.
The report is wordy and repetitive, but readers who want a
quick overview can review the Executive Summary or focus on Table 2.1, which
explains the GHG emissions-reduction strategies at three levels of deployment;
Table 4.1, which shows the implementation costs and changes in vehicle costs for
the strategies; and Table 4.2, which projects the yearly reductions in GHG
emissions that would be achieved by the strategies. Policymakers may want to
study the Findings section; data hounds can dig into the 290-page Technical
Appendices.