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Open Access Publications from the University of California

"Intelligent" Ways to Cut Transportation's CO2 Emissions

  • Author(s): Barth, Matthew
  • Boriboonsomsin, Kanok
  • et al.

Most policies to cut the transportation sector’s CO2 emissions focus on fuel-efficient vehicles, low-carbon fuels, and reductions in vehicle-miles traveled. One strategy that gets less attention but has high potential pay-off is Intelligent Transportation Systems (ITS). An example is variable speed limits on freeways, illustrated in the photo below. Under this scheme, motorists are alerted of downstream congestion and the adjusted posted speed limits help maintain a steadier, more even flow. Reducing the amount of stop-and-go traffic can significantly cut down on tailpipe emissions and fuel waste.

Some studies suggest that the carbon reduction benefits of ITS are minimal. For example, the recently released “Moving Cooler” report, prepared by Cambridge Systematics, estimates that ITS would reduce emissions by less than 1% nationwide. Others contend that ITS projects could induce new travel that offset some of the gains. We believe that these analyses fail to include key calculations that cast ITS in a more favorable light.

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