As Stanford University's massive hospital expansion glides toward Palo Alto's approval, its projected impacts on local traffic and the environment are gradually becoming less intense and more manageable, the latest environmental documents show.

The project's Final Environmental Impact Report (FEIR) -- a voluminous, comprehensive document that the city's Planning and Transportation Commission began to review Wednesday night (March 9) -- paints a more benign picture of the expanded hospital's impacts than the document's draft version. After Palo Alto's planning staff and environmental consultants reviewed more than 1,000 individual comments about the draft EIR, they concluded that these comments don't introduce any significant new issues that the document hadn't already explored.

At the same time, some of the impacts that the earlier document listed as "significant and unavoidable" are now considered to be manageable. The number of significant and unavoidable impacts fell from 17 in the earlier document to 12 in the new one, consultant Rod Jeung from the firm PBS&J told the planning commission.

The revisions surprised some of the planning commissioners, including Susan Fineberg, who found it hard to believe that the trove of new comments didn't unearth any new issues.

"I find it absolutely phenomenally extraordinary, to the point that the only way I can characterize is as absolutely unbelievable," Fineberg said. "And I'm not sure it's a positive or a negative.

"Logic tells me that with that many eyeballs on the document and with that many people looking at things, somebody can find something somewhere that can't be dealt with with a new mitigation or a dismissal through legal, technical, analytic, empiric jargon."

Stanford's hospital project would add 1.3 million square feet of development and an estimated 2,242 new employees to Palo Alto. It includes a new Stanford Hospital & Clinics building, an expansion to the Lucile Packard Children's Hospital, and renovations to various Stanford School of Medicine buildings.

Staff and consultants have been reviewing the project's impacts since 2007 and the City Council plans to approve the hospital expansion this spring. Approval includes certification of the FEIR, which lists all of the project's impacts and mitigations.

Some of the most notable changes in the FEIR pertain to the project's impacts on Menlo Park traffic. Since the draft was released, the consultants learned more about the city's traffic-adaptive signal technology and concluded that some of these impacts won't be as bad as they initially thought, Jeung said.

Menlo Park officials are also reviewing the FEIR this month. To give them time to complete their review and submit their comments, Palo Alto commissioners agreed Wednesday to delay their vote on the document.

The changes in the new document include a revised projection of the expansion's impact on two Menlo Park intersections: El Camino Real and Ravenswood Avenue, and Santa Cruz Avenue and Sand Hill Road. The draft EIR called the traffic impacts to these two intersections "significant and unavoidable." The new document comes to a different conclusion.

"After further analysis and consideration of existing traffic-adaptive signal technology, the environmental consultants decided that these intersections would no longer be significantly impacted by the hospital expansion," the final EIR states.

The revised document also scaled down the projected impacts to two other Menlo Park intersections: Middlefield and Willow roads and Middlefield Road and Ravenswood Avenue. The impacts, previously listed as significant, are now "less than significant."

In the earlier document, consultants assumed that 13 intersections (mostly along El Camino Real in Menlo Park) don't use traffic-adaptive signal technology. Since then, they learned that this technology is already being used.

The new document states that "given the current traffic-adaptive signal technology at these intersections, the modified intersection analysis for these intersections indicates that they would no longer be significantly impacted by the SUMC project."

Several speakers asked the planning commission to review some of the EIR's assumptions and consider additional mitigations.

George Mader, who served as Portola Valley's town planner for 45 years and who is now the town's planning consultant, raised questions about about the project's impacts on several busy intersections, most notably on Alpine Road between Junipero Serra and the on-ramp to Interstate Highway 280.

He urged the commission to require that Stanford periodically monitor the traffic levels at some of these intersections to make sure they are aligned with the EIR's projections.

Michael Griffin, a former Palo Alto planning commissioner, also expressed skepticism about the new document's traffic projections. He warned that the hospital expansion could worsen the congestion on several busy intersections, including sections of Willow and Page Mill roads near highway off-ramps.

Stanford's proposed traffic mitigations include buying Caltrain Go Passes for all hospital employees, and various pedestrian and bicycle improvements. Griffin said it's not clear these measures would sufficiently mitigate the increased congestion.

"We are betting all in on the validity of the Palo Alto traffic-forecast model," Griffin told the commission. "I hope we know what we're doing here, with all due respect to staff."

The commission asked questions about some of the document's assumptions and methodologies, including its decision to downgrade some of the impacts from "significant" to "less than significant" levels. Toward the end of the meeting, Commissioner Arthur Keller said that some of the impacts could be insignificant by themselves but could lead to greater disruption when combined.

"It seems to me that a lot of traffic and housing impacts are like Chinese water torture," Keller said. "Every individual drop has very little effect, but cumulatively they can dig a Grand Canyon."