Two long-envisioned North Bay transportation projects are under renewed scrutiny as regional planners put together a new $200 billion spending plan.

The two projects — widening the Novato Narrows and Sonoma-Marin Area Rail Transit extensions to Cloverdale and Larkspur — are in the current regional plan, a listing that is necessary to be eligible for state and federal funds.

But they are now being subjected to a fresh level of analysis as the Metropolitan Transportation Commission crafts a new regional plan, scheduled to be adopted in mid 2013 and take effect in 2015.

"The commission will want to take a closer look at both of these projects and look not only at cost-benefit, but at the history," MTC spokesman John Goodwin said. "In each case there is significant support, but it would be vastly presumptuous to declare any likely outcome."

MTC's ranking now includes a cost-benefit ratio based on construction cost and a reduction in travel times.

Additionally, the MTC is also considering the impact on greenhouse gases, fossil fuel use, reducing traffic congestion, improving safety, serving housing needs and the availability of transit for low-income residents.

Unfortunately, that analysis benefits projects in the more heavily-populated areas of Oakland, San Francisco and San Jose to the detriment of Sonoma County, said Suzanne Smith, executive director of the Sonoma County Transportation Authority.

"Just because we are not an urban, densely-populated area, it doesn't mean we don't have transportation needs," Smith said.

In one MTC analysis, the SMART extensions, estimated to cost $283 million, have a poor cost-benefit ratio compared to road and other transit projects, but have environmental benefits and support from voters who approved a quarter-cent sales tax.

For the widening of the Narrows between Petaluma and Novato, which will cost $300 million to complete, the cost-benefit ratio is acceptable. However, the widening will only add vehicles to Highway 101, and increase emissions, greenhouse gases and other negative environmental impacts, according to the MTC evaluation.

Those two projects are now considered regionally significant and are included in the current MTC regional plan.

"They are still viable on a regional level and when final arguments are made, they may survive," said Rohnert Park Mayor Jake Mackenzie, an MTC commissioner. "I would say they will be under a lot of scrutiny, but we knew that anyway."

The regional plan also looks at plans to build a $1.46 million regional network of bikeways in the Bay Area, including Sonoma County. The proposal has a high cost-benefit ratio, because of its relatively low cost compared to the number of cars it is expected to take off the road, as well as environmental and health benefits.

A proposal to spend $428 million to expand bus transit in Sonoma County gets a low cost-benefit mark, but there are still many environmental benefits, according to the MTC analysis.

The MTC expects to receive $200 billion in funds between 2015 and 2040 that will be generated by all local, regional, state and federal sources, from local sales taxes to federal gas taxes.

Seventy percent of that will be used to maintain the current transportation system, including road repairs and mass transit, leaving 30 percent for expansions and new projects.

Planners for Sonoma County expects its share to be $967 million in funds from 2015 to 2040. They propose spending $267.8 million for a SMART extension from Santa Rosa to Cloverdale, $200 million for widening Highway 101 in the Narrows and $95 million in bikeways.

Marin County officials, however, say they will include money for the SMART extension from San Rafael to Larkspur in its proposals only after SMART has the Santa Rosa-San Rafael segment in operation.

"It is not that we don't support SMART. We have this tiny pot of state gas tax money, and we have elected to spend it on other things, like finish the Narrows," said Dianne Steinhauser, executive director of the Transportation Authority of Marin.