Transportation infrastructure projects are a key component of economic stimulus, especially for the construction sector, which has been hit twice over the last two years – first by the housing crash and then by the wider economic crash.

"Shovel-ready" projects will bring immediate economic relief and, potentially, long-term benefits.

The metropolitan planning organization responsible for the Sacramento area, SACOG, is compiling a long list of "shovel-ready" transportation projects, with city and county governments across the region throwing all viable projects into the hopper for stimulus funding.

The draft list, scheduled for a vote by the SACOG board on Thursday, totals almost $3 billion – easily enough to meet the capacity of the region's construction firms. However, choosing prudently from the long list of projects sets a new kind of challenge for agency staff members and policymakers. They have an opportunity, unique in recent times, to prioritize transportation projects based not only on economic factors and perceived need, but also based on the state's new goals for reducing greenhouse gas emissions. This fundamentally changes the economic nature of the choices available.

The list includes several dozen big-ticket highway expansion projects that have been on the books for up to 20 years, awaiting funding. Developed at a time when greenhouse gases were not a concern, these projects range from the widening of arterial roads to the addition of more freeway lanes. While providing a short-term economic stimulus, these projects would bind the state to the long-term costs of mitigating the greenhouse gas emissions that increased roadway capacity creates.

Increased roadway capacity leads to more emissions because drivers increase the number and distance of their trips in response to reduced congestion. An increase of, say, 20 percent in roadway capacity leads to a 10 percent to 20 percent long-term increase in driving. This means that any reduction in congestion is quickly lost, while tailpipe emissions and the total amount of time spent in cars both increase, with knock-on effects on public health, safety and lost productivity.

In July, the California Department of Transportation lost a lawsuit in part over its failure to inform the public of the increases in driving and greenhouse gases that would result from the addition of freeway lanes to Highway 50.

There are many projects that would provide needed economic stimulus without creating future financial and political burdens. For instance, simple roadway maintenance is sorely needed in the Sacramento area: A report in March pegged Sacramento as the eighth-worst out of 68 major urban areas in terms of pavement conditions, with every Sacramento driver paying $655 annually in additional vehicle maintenance costs.

Road maintenance projects create opportunities for "complete streets" with improved bicycling, walking and public safety, by striping crosswalks and bike lanes when pavements are resurfaced.

Public transit projects can also provide a major economic stimulus, and they have the potential to reduce greenhouses gases compared with vehicle use. Transit also improves mobility for people who do not drive, increasing their ability to contribute to the economy.

"Safe Routes to Schools" projects create safer neighborhoods for walking and reduce morning bottlenecks around schools. Bicycle route improvements allow more people to make the choice to ride, which benefits both cyclists and drivers. Dozens of these projects are on the SACOG list of immediate stimulus options.

Of the $3 billion in potential projects on the list, around half the dollar value is represented by projects that will increase greenhouses gas emissions, while the other half would either have no effect or would reduce emissions. Spending stimulus funds on increasing highway capacity, and thus neighborhood traffic and greenhouse gas emissions, would be an expensive mistake that would set back public safety, compromise urban revitalization and redevelopment projects, and add to future costs of mitigating greenhouse gas increases.

Prudent choices over the coming weeks could put Sacramento at the front of the pack of California regions, in a good position to leverage future federal funding.

Leadership from SACOG, local governments, and Caltrans is required to choose the right infrastructure projects to put the region on track for recovery.

Owen Howlett serves on the board of directors of the Sacramento Area Bicycle Advocates (SABA) and the Environmental Council of Sacramento (ECOS).