SPUR’s report Critical Cooling recommends 42 options for reducing local carbon emissions. This is one of them. To learn about all 42 ideas, read the full report

Implement Bicycle Improvements

One of 42 options for reducing local carbon emissions, from our report Critical Cooling.

Urbanist Article
Annual savings potential:
Annual public cost:
Public cost per ton:
Implementing agency:
Horizon year:
47,500 tons
$13.1 million
Municipal Transportation Agency


  • An additional 30 miles of new bike lanes
  • Complete resurfacing of existing and new bike lanes
  • Approximately 25 miles of new bicycle paths
  • Annual educational and promotional costs of approximately $1 million
  • Approximately 50 miles of traffic-calmed streets
  • 31 percent of all new bicycle trips will replace driver trips.
  • The length of the average auto trip replaced will be 3.3 miles.
  • Bicycle trips will increase from 2 percent of all trips to 9 percent of all trips.


Phase 2 bicycle network improvements are more expensive than Phase 1 improvements, but have about the same cost per ton. Bicycle network improvements should be justified not on the basis of emissions reductions, but rather on how they improve urban livability and make low-traffic, high-density development possible.

What we do now
The 2008 San Francisco Bicycle Plan Update, currently in environmental review and expected to be approved in the summer of 2009, provides an outline for the next phase in bicycle improvements for the city, proposing about 34 miles of new bike lanes. This is estimated to increase the rate of bicycling by about 50 percent, or from about 2 percent to 3 percent of all trips. The original Bicycle Plan’s stated goal, however, is for 10 percent of all trips to be made by bicycle. This would be nearly the proportion of trips made in Portland, Ore, somewhat less than in Davis, and about one fourth less the proportion of trips made in the most bicycle-friendly cities in Europe, such as Copenhagen, Amsterdam, Groenigen and Freiburg.

What we could do
Achieving this mode share as proposed in Phase 2 will have significantly more cost than is proposed by the 2008 Bicycle Plan and have significantly more carbon emissions reduction benefits than can be achieved by this plan. Phase 2 includes more costly measures excluded in Phase 1, such as about 25 miles of new and improved separated bicycle paths, including expensive reconfiguration of Market Street and the Embarcadero; new bridges where appropriate, such as the proposed bicycle bridge over Seventh Street that is part of the Mission Creek Bicycle Path proposal; and traffic calming on low-volume residential streets. The goal is to create a contiguous network that is safe for users of all abilities and ages, from young children to senior citizens.

The estimated capital cost of the improvements named in the bike plan is $171 million and the incremental operating cost is about $30 million. Financed at 5 percent over 30 years, these projects will cost $13.1 million per year.

Carbon savings potential
If we assume that an investment of this level will increase the amount of bicycling to 9 percent of all trips, it will lead to an additional 127 million new bike trips per year. If we further assume that bike trips will shift away from other modes in proportion to each other mode’s current share of all internal San Francisco trips, then about 31 percent of all new bicycle trips will replace driver trips. At the average internal trip length of 3.3 miles, the investments will save 133 million vehicle miles traveled per year, or 47,460 metric tons of CO2. The cost per ton of CO2 emissions abatement would be $276.