The Dumbarton Bridge will be closed to traffic Memorial Day weekend to allow Caltrans and its contractor to significantly advance seismic retrofit work on the bridge, according to bridge officials.

Effie Milionis, a spokeswoman for the Dumbarton Bridge Seismic Safety Project, said that the three-plus-day closure will permit Caltrans to replace a major seismic joint across all six lanes of traffic on the bridge's western side.

The 1.6-mile Dumbarton Bridge, which spans from Menlo Park to Fremont, carries approximately 60,000 vehicles daily. In the event of an earthquake, the seismic joint will absorb and dissipate energy.

Milionis said completing the seismic joint is a significant milestone in the retrofit project, which began in 2010 and is expected to be completed next year.

The bridge will be closed from 10 p.m. Friday, May 25, to 5 a.m. Tuesday, May 29, Milionis said.

Motorists should plan ahead, allowing extra travel time to take alternate routes, including the San Mateo-Hayward Bridge. Suggested detour routes are available at dumbartonbridgeinfo.org.

In a Northern California first, work is under way to install double carpool lanes in both directions on a freeway.

The new lanes will be built along a three-mile stretch of Highway 101 between Highway 85 in Mountain View and Embarcadero Road in Palo Alto.

Along with merging lanes also being built, the new look will turn this section into one of the widest in the region, with 12 lanes. And all the extra asphalt also offers a glimpse into our commuting future.

The widening sets the stage for more toll lanes, including a second set of carpool lanes up and down 101 from Morgan Hill to the San Mateo County border.

In the next year or two, the eastbound Interstate 580 carpool lane in the Tri-Valley will be widened to include two toll lanes, also known as express lanes. And by 2015, a second set of carpool lanes could line Highway 85 through the Almaden Valley area of South San Jose.

Currently, there are double carpool lanes only on the approaches to the toll plazas at the San Mateo and Bay bridges, but none on area freeways except for short stretches where two carpool lanes merge at interchanges.

"All else equal, two lanes per direction makes for a better (toll) lane than one per direction," said Bob Poole, transportation director of the Reason Foundation think tank. "You can pass slow vehicles, be more flexible in case of a breakdown or accident, etc.

"And you can charge a lower toll if you have two lanes to accommodate paying customers instead of one."

Highway 101 ranks as one of the toughest commutes in the South Bay, and the stretch from Shoreline Boulevard north to Palo Alto is perhaps the nastiest. As the economy improves and more drivers join the commute, traffic jams will only get worse.

But a second set of carpool and merging lanes could ease the frequent lane changing that contributes mightily to slowdowns on this freeway. Motorists often slow to speeds under 20 mph as they approach their exits, leading trailing drivers to slam on their brakes.

"It's scary," said Megan Vaughn, 29, of San Jose. "I've seen people in the carpool lane literally stop when trying to move over for their exit. I hope a second carpool lane would bring an end to this."

Added Ed Mullen, a 51-year-old accountant from Mountain View: "The ride home is usually heavy or stop-and-go. A lot of the time the HOV lane is only moving slightly better than the rest of us, so I would guess there are enough frustrated drivers that would pay to move a little quicker."

Despite a decline in overall carpooling nationwide over the past two decades, diamond lanes on some Bay Area freeways -- including 101, I-80 and I-880 -- are filling up. It's common, engineers and commuters say, to find carpool traffic barely moving faster than lanes filled by solo drivers.

Bound by federal mandates to keep carpool-lane speeds flowing at 45 mph or faster, traffic planners say they have few choices to ease commutes and raise the money to pay for more road work. They can require carpools to contain three people instead of two, or they can add a second carpool lane.

"Increasing the occupancy requirement may be the logical solution if adding a second carpool lane is inappropriate," said Caltrans' Joseph Rouse, who oversees carpool lanes in the state. "However, going from two-plus to three-plus (occupants) may reduce vehicular demand by 75 to 85 percent. Such an adjustment may be too severe if

only a 10 percent to 20 percent reduction is necessary to maintain free-flow conditions."

As usual, Southern California is ahead of the Bay Area in testing the new approach. There are double carpool lanes on I-5 for a couple of miles south of I-405 in Orange County, and on I-110 in Los Angeles from I-105 to south of downtown Los Angeles. And there are projects under way to add double carpool lanes on I-10 and along more of I-110 in Los Angeles.

There are also two express lanes in each direction on Route 91 in Orange County, with an extension planned into Riverside County. And there are two express lanes in each direction on I-15 north of San Diego.

Not all freeways will get a second carpool lane, usually because there isn't room to add more than one. That's the case on I-880 through San Jose, where a carpool lane is being added, and on I-80 east of the Bay Bridge.

The widening of I-880 in the South Bay will run from Highway 237 almost to 101, with major changes scheduled for the Brokaw Road interchange. A carpool lane will be added on the southbound onramp and the merge lane extended 700 feet.

On the northbound side, the ramps will be shifted 70 feet east and there will be two lanes to turn left and two more to turn right. The tight, curvy two-lane ramp to north 880 will be smoothed out.

California legislators should deny Gov. Jerry Brown's requests for all but minimal funding for the California High-Speed Rail Authority in the current budget process, the Legislative Analyst's Office recommended Tuesday, April 17.

The nonpartisan analyst's office, which provides fiscal and policy advice to the Legislature, said the rail authority has failed to provide sufficient detail and justification for its plan to build a high-speed train system.

"Specifically, funding for the project remains highly speculative and important details have not been sorted out," Legislative Analyst Mac Taylor said in a 12-page report.

In its most recent business plan, the rail authority projected the first phase of the project will cost $68 billion. However, the authority has secured only about $9 billion in voter-approved bond funds and $3.5 billion in federal funds.

Consistent with the new business plan, Brown's 2012-13 budget plan requests $5.9 billion to continue the project, consisting of $2.6 billion in state bond funds matched with $3.3 billion in federal funds to start construction in the Central Valley.

In addition, about $800 million is requested to improve existing passenger rail services and about $250 million to complete preliminary design work and environmental reviews for various sections of the project.

"In this brief report, we find that HSRA has not provided sufficient detail and justification to the Legislature regarding its plan to build a high-speed train system," the analyst said.

"We recommend the Legislature not approve the governor's various budget proposals to provide additional funding for the project. However, we do recommend that some minimal funding be provided to continue planning efforts that are currently underway."

Caltrain is one step closer to receiving the electrification and modernization officials say the system desperately needs.

An agreement between the California High-Speed Rail Authority and more than half a dozen Bay Area public agencies will entirely fund an upgrade to the system, which includes modernization, agency spokeswoman Christine Dunn announced in a statement Thursday morning.

According to Dunn, the funding agreement uses local, regional and federal dollars to leverage hundreds of millions of dollars matched by the high-speed rail authority.

The electrification and modernization of Caltrain have been in the works for more than a decade, and are "critically-needed improvements that will dramatically improve the service and help ensure the long-term viability of the commuter rail system," Dunn said in the statement.

The announcement comes just a week after Assemblyman Jerry Hill, D-San Mateo, urged Peninsula residents at a news conference at the San Mateo Caltrain Station to get on board with the electrification of Caltrain.

Once the system is electrified, Caltrain will be able to operate lighter-weight electric vehicles with major performance advantages compared to the existing diesel rail technology.

Trains will be faster, cleaner, quieter and more efficient, according to Caltrain officials.

In addition, riders will see more frequent service to more stations, which will result in increased ridership and prepare the system to accommodate future job growth.

Modernizing Caltrain is also an important step in stabilizing the rail agency’s long-struggling finances. Caltrain is one of the few transit agencies in the country that does not have its own, dedicated tax base or source of revenue.

“Electrification is an essential improvement that is critical to the future of the system,” Executive Director Mike Scanlon said in a statement.

“This is an enormous step forward that prioritizes these improvements and delivers early benefits to the Caltrain system, its riders and surrounding communities,” he said.

Plans for the electrification of Caltrain still need to be approved by the Metropolitan Transportation Commission at its meeting next week, as well as the boards of all the public agencies, and the state legislature will also need to sign off on the bond, Caltrain spokesman Seamus Murphy said.

If approved, Caltrain could be electrified as soon as 2020, more than a decade before it is assumed in the most recent version of the High Speed Rail Business Plan.

Caltrain is currently assessing the possibilities of various blended system alternatives to the four-track system, which the agency opposes, to determine what specific infrastructure improvements will eventually be needed to support high-speed rail and how they can be designed to minimize impacts on surrounding communities.

Four years after California voters passed a bond measure to help fund a high-speed rail system, many now feel let down because of skyrocketing costs— heightened by the state's fiscal crisis—and the Rail Authority's controversial draft business plan and estimates.

Dan Richard, chairman of the California High-Speed Rail Authority (CA-HSRA), said Tuesday, however, that "the governor told us the number will come down" from the current $98.1 billion.

The pricetag and other concerns–like the California High Speed Rail Authority's decision to begin construction in the Central Valley versus the "bookend" urban areas of San Francisco and Anaheim–were raised during a legislative hearing in Mountain View's Center for the Performing Arts hosted by the Senate Select Committee on High Speed Rail on Tuesday night.

"We are all supportive of high-speed rail, but it has to be high-speed rail done right, and decisions made against the best available evidence, use of money, and not based on political decisions," said State Senator Alan Lowenthal (D-Long Beach), co-chair of the committee with Joe Simitian (D-Palo Alto).

The high-speed rail project, which the CA-HSRA Draft Business Plan and Senate Select Committe estimates place the higher-end cost at $118 billion, prompted many in the 600-seat auditorium to demand that Proposition 1A be placed on the ballot again. Proposition 1A, which voters passed in 2008, raised $10 billion in bond financing for high-speed rail. Some voters expressed regret for voting for the proposition, based on recent developments.

"I wouldn't have voted for it knowing what I know now," said one attendee.

Richard and Board Member Jim Harnett carefully answered questions fired off to them by Simitian and Lowenthal. Their determination and commitment to the project remained resolute.

"No regional transportation plan is predicated on knowing where all the money is coming from at this stage," Richard said. "I can't look you in the eye and say that we have any greater clarity about the funding today but we'll have a more rational basis [in the future]."

He also added that "the ultimate rider projections show there will be enough riders so that they won't need a public subsidy."

This was rebutted in public comments by residents concerned about the validity of those projections.

Richard told Mountain View Patch at the conclusion of the six hour meeting that the CA-HSRA would "absolutely" be interested in private sector money.

"There is a lot of private sector interest, but we have to get it built first," he said, adding that they want to be conservative about how much they could get. He said around $20 billion. "The private sector would need to see the ridership figures first."

Under continuous consideration is the $760 million high-speed rail funds that could go toward the electrification of Caltrain, but that remain contingent–because of the language of Prop 1A–on the construction of the entire system.

Assemblyman Jerry Hill, in attendance, had held a press conference in San Mateo earlier that day to encourage residents to support electrification for the commuter rail.

Also, the potential loss of the $2.5 billion in federal American Recovery and Reinvestment Act funds that must be committed to the high-speed rail project by Sept. 30, 2012 in order to be allocated.

William Kempton, chairman of the HSR Peer Review Group, and Legislative Analyst's Office staff Farra Bracht and Brian Weatherford, also raised concerns about the analysis of the CA-HSRA.

There was a mixed bag of opinions during the public comments, which began first with statements from elected officials. Mountain View Councilwoman Ronit Bryant attended the meeting, however no elected member of Mountain View spoke on the record about the project.

The strongest opposition continued to come from Palo Altans and residents of San Mateo County.

Palo Alto Mayor Yiaway Yeh asked the State to eliminate the project. Atherton City Councilman Jerry Carlson said that "nothing I've heard tonight changes our mind," and that the funds should be used for other projects. He and Palo Alto Councilman Patrick Burke called for the Metropolitan Transportation Commission (MTC) to stop dictating what happens in the Peninsula.

Burlingame Councilwoman Terry Nagel said that "we are not against it if it's done right," but to be done right the CA-HSRA needs to listen to all cities affected along the Caltrain corridor. One of her constituents, Karen Perry, express her fear of losing her home.

Almost all speakers acknowledged and called this new board more "amenable" than the last.

Parties in favor of the project included the labor unions, the mayors of San Francisco and San Jose, and San Francisco Airport Director John Martin.

Cupertino Councilman Barry Chang, and others, spoke to the environmental benefits of getting people out of their cars because "we can't rely on fossil fuels." The potential reduction of vehicular deaths and the duty of goverment to enhance safety were also raised.

William Sandie of Los Altos, among others, hoped to see a French-style or Japanese-style high-speed rail system. He believed it a good idea to start to build in the Central Valley. The Central Valley portion, called by several the "train to nowhere" is part of the CA-HSR's "Initial Construction Segment" and has $6 billion dollars apportioned for it.

"Should we not have built I-5 because not enough people live between Sacramento and Los Angeles?" he said. "We didn't know then where the funds would come from."

But if the project does move forward, all begged the state senatoros to hold the Authority to greater standard. They want not only more transparency, but a solid business plan.

The Authority, however, is also aware of their limitations.

"We made an effort to show voters what it would cost over 20 years," Richard said. "Frankly, the voters also provided that the legislature would make the final call. It's built into the law."

A final 2012 Business Plan is expected to be released late March 2012.

A lower price tag, fewer tracks and a fresh commitment to fund rail improvements in north and south California are among the features that the California High-Speed Rail Authority plans to unveil in its revised business plan, rail officials told a state Senate committee Tuesday night, March 13, at a public hearing in Mountain View.

The revised plan, which the rail authority's board of directors plans to release later this month, will also emphasize more than previous documents what has become known as the "blended" approach for the rail system -- a design that would have the new rail system share two tracks with Caltrain along the Peninsula cabinet. This design, which was proposed by state Sen. Joe Simitian, D-Palo Alto, U.S. Rep. Anna Eshoo, D-Palo Alto, and Assemblyman Rich Gordon, D-Menlo Park, a year ago, has been the subject of much debate in recent months, with many city officials along the Peninsula urging the rail authority to commit to the two-track alternative.

On Tuesday, rail officials indicated that with the new business plan, they are preparing to do just that. Dan Richard, chair of the rail authority's board of directors, and Jim Hartnett, a board member, both said that the "blended" approach is central to the agency's new vision for the project. The members made these comments at a meeting hosted by Simitian, who chairs a Senate budget committee on resources, environmental protection and transportation.

Last year, rail officials resisted the "blended approach," suggesting that it would run counter to Proposition 1A, a $9.95 billion bond for the rail system that voters approved in 2008. The agency's latest environmental analysis for the major project sill refers to a four-track system, much to the consternation of officials in Palo Alto and elsewhere.

But Hartnett said Tuesday that the agency, in its revised plan, now embraces the idea of a "blended system" for both the northern and the southern sections of the San Francisco-to-Los Angeles system. Hartnett called the new emphasis on the "blended system" a "rethinking of the whole high-speed-rail approach."

"The new direction for high-speed rail is a high-speed-rail system that is dependent on its success on a blended approach both in the north and in the south," Hartnett said.

This new vision could have dramatic implications for Caltrain, which has also been adamant about scrapping the four-track design in favor of the less disruptive blended system. The new business plan, Hartnett said, would place greater emphasis on relying on existing infrastructure in the what the rail authority is calling the "bookends" of the line (its northern and southern segments). Specifically, he said, it will lay out a plan for "early investment in the north and in the south that will have direct positive impact on the regional transit systems" and lay the foundation for high-speed rail.

For Caltrain, this early investment could mean getting the funding it needs for electrification -- a project that the cash-strapped agency has been planning for more than a decade. The project, which the agency sees as key to raising its ridership numbers and achieving long-term financial stability, also includes positive train controls and a new stock of electric trains. It would cost more than $1 billion, money that the agency currently does not have.

The rail authority's new vision for the rail system could change that. The rail authority is preparing a "memorandum of understanding" with the Metropolitan Transportation Authority that would identify "early investment opportunities" that the authority can make in the Bay Area. Though the document is still in the works, Caltrain electrification is widely expected to top the list of Bay Area's transit priorities.

"This is an opportunity for Caltrain as much as it is an opportunity for high-speed rail," Hartnett said, referring to the early investment. "We believe the plan will set out a reasonable way of doing that."

But even as they talked about making early investment in the "bookends," rail officials defended on Tuesday the authority's decision to begin the line's construction in Central Valley. This decision had prompted many critics of the $98.5 billion project to refer to the system as a "train from nowhere to nowhere." Some, including the agency's own peer review group, have challenged its earlier business plan for inadequate discussion of funding sources and for its vagueness in discussing plans to build the system beyond the initial segment.

Aside from the voter-approved bond and about $3 billion in federal funding, the project has no other committed funding. The agency's business plan anticipates private investment in the later stages of the project.

The challenge, Richard said, is to demonstrate that the first segment of the line would provide significant improvements even if the agency doesn't get the funding it needs to build the entire system. The revised business plan, he said, "will have a more rational basis for showing how the system develops over time so that each station that we'll have in front us we'll have something that is useful -- like Caltrain electrification, for example."

Richard, who was recently appointed to the board of directors by Gov. Jerry Brown, defended the decision to start in the Central Valley. Starting the rail system in this region will allow the agency to test the new 225 mph trains. On the Peninsula, the trains would reach speeds of up to 125 mph.

Richard also said the agency believes that the new system's ridership will be sufficient to cover its operating costs. The rail authority's ridership and revenue numbers have been a subject of major criticism on the Peninsula and elsewhere. Uncertainties over these projections, along with the project's escalating costs, were among the major factors that prompted the Palo Alto City Council to officially adopt a position last year calling for the project's termination.

But Richard said that the numbers show that even in the line's "initial operating segment" (the first constructed segment that would be capable of accommodating high-speed trains), ridership would be sufficient to pay for operations.

"We believe that the ultimate ridership projections will mean that there will be sufficient riders on the high-speed rail so that we will not be needing a public subsidy in order to operate," Richard said.

Though Richard did not specify how much the rail system would cost under the "blended" approach, he said the number will come down from the prior estimate of $98.5 billion. He called the price tag (which was a major jump from the agency's prior estimate of about $40 billion), a "sticker shock" for many people. It will be incumbent for the agency to show, in its new business plan, the ways in which the capital costs can be reduced.

"The key to it is the blend approach," Richard said. "This is one of the things that will lock us into the course that I think will save us a lot of money."

Though the rail authority's new vision is more consistent with the views of many Peninsula officials, some said Tuesday that they remain skeptical about the latest plans. Palo Alto Councilman Pat Burt, who chairs the Peninsula Cities Consortium (a coalition that also includes Atherton, Menlo Park, Belmont, Burlingame and Brisbane) said that when it comes to early investment opportunities in the Peninsula, the "devil will be in the details" of the agreement between the rail authority and the MTC. He noted that the MTC signaled that cities along the Peninsula would not have any direct participation in the process.

Burlingame Councilwoman Terry Nagel also said she is concerned about the MTC's ability to adequately represent the Peninsula cities in the "eleventh hour."

"I don't think the majority of the cities are opposed to high-speed rail if it's done right and that's a big if," Nagel said. "It would require money that is well spent on the Peninsula."

If one believes regional projections, Palo Alto will have to build 12,500 new homes by 2035 to accommodate job growth and meet California's ambitious green goals.

Count the City Council among the skeptics.

Over the past two years, city officials have been pushing back against the planning scenarios put forth by the Metropolitan Transportation Commission (MTC) and the Association of Bay Area Governments (ABAG), the agencies charged with implementing in the Bay Area the state's landmark greenhouse-gas-reduction law, Senate Bill 375. The agencies' aim is to comply with SB 375's lofty goal of achieving a 15 percent reduction in greenhouse-gas emissions between 2005 and 2035. A key part of the plan is encouraging cities to build housing near jobs and transit corridors, thereby reducing traffic.

But what if the state's population projections are way off? And what about cities that don't have the land or resources to plan for the required housing? Palo Alto officials have been asking these questions for months and have yet to receive answers that satisfy them. They have challenged ABAG and MTC's growth estimates and, last month, requested that growth projections by the state Department of Finance undergo a peer review.

The regional agencies are relying on state projections showing that the Bay Area will need to accommodate an additional 903,000 housing units and 1.2 million jobs between 2010 and 2035. The agencies have released three alternative scenarios, two of which would require Palo Alto to plan for more than 12,000 housing units, while the third one, known as the "outward growth scenario," transfers more burden to smaller cities and pegs the Palo Alto number at about 6,100.

The projections have irked council members, however. Councilman Greg Schmid, an economist with a penchant for strategic planning, has emerged as the council's staunchest skeptic. In November, Schmid surveyed a variety of growth projections made before 2005, including ones from UC Berkeley academics and from UCLA's Anderson School of Accounting, and found many of them (including the Department of Finance's) to be far too optimistic about growth rates. He cited a report from the Public Policy Institute of California that included population projections of all key demographic forecasters. The consensus forecast from this group, he noted, was 40 percent higher than the actual outcome.

Schmid also noted in his report that the Department of Finance used projections that are far higher than those used by the U.S. Census Bureau.

"Even as late as the end of 2009, on the eve of the decennial census, estimates by the California Dept. of Finance (the organization responsible for the numbers that are used for all state allocation formulas) remained strikingly high at 14.1 percent, which was 1.5 million or 44.7 percent above the contemporaneous and more accurate Census Bureau's Current Population Estimates," Schmid wrote.

The dispute is more than an academic debate over statistics. Though ABAG and MTC can't force cities to accept their projections, they can withhold transportation grants from those agencies that don't comply. Palo Alto officials have been cooperating with the agencies by identifying areas of the city that could accommodate growth. Much of the new housing would cluster around California Avenue, Palo Alto's designated "priority development area." Other transit-friendly parts of the city, including portions of downtown and around El Camino Real, are also seen as ripe for growth and the council is scheduled to consider in the coming weeks whether to designate them priority development areas as well.

Under the regional proposal, development of these areas would be bolstered by state grants. The agencies plan to allocate about $66 million in grants to Santa Clara County, with 70 percent going to "priority development areas." Palo Alto, which seeks to upgrade its biking network and renovate the streetscape at California Avenue, is banking on grants to make its vision a reality. At the Dec. 5 council meeting, Councilwoman Nancy Shepherd said she doesn't want to "walk away from transportation dollars because we desperately need them."

But while the council has been working on identifying growth-friendly areas, members have consistently argued that Palo Alto has nowhere near the capacity for new housing that the agencies require to meet the goals outlined in their Initial Vision Scenario.

The council's dilemma may sound familiar to those who followed the city's three-year battle against high-speed rail -- another project that members supported in principle but then turned against because of concerns about how it's being implemented. Much like with high-speed rail, the council formed a new committee last month to focus on regional housing allocations. The committee is scheduled to hold its first meeting Thursday, at which point it will consider whether to designate El Camino Real and downtown "priority development areas," making them eligible for transportation-grant funds.

In a recent interview with the Weekly, City Manager James Keene predicted that Palo Alto would take the lead in the regional conversation over housing allocation, much as it had in taking a skeptical stance toward the increasingly controversial rail system.

Shepherd also compared her frustration with ABAG's statistics to her experiences with the California High-Speed Rail Authority.

"I'm worn down with high-speed rail already with trying to come up with reasonable questions, with trying to put together clear data and trying to get people to respond ... to a lack of credibility with the numbers we're using," Shepherd said at the Dec. 5 meeting. "And it sounds like we're walking right back into this again with these ABAG numbers."

At the same meeting, Councilman Larry Klein was one of several members who said the city should demand a better explanation of how the Department of Finance had come up with its numbers. The projections, he argued, need to be subject to more public scrutiny.

"I think we have to really not accept it (the state projection on future jobs) and say, 'Let's have some public discussion of where the numbers come from," Klein said.

Shepherd joined Klein in praising Schmid's report and said the numbers used by the regional agencies give her "great concern" because the city is asked to do a lot of work to accommodate the housing projections.

Curtis Williams, the city's planning director, highlighted a number of concerns in a report last month. Economic projections, he wrote, "appear to be substantially overstated" and the regional housing projections are too high and are "driven by unrealistic employment projections."

"The basic goal of reducing greenhouse gas emissions is not well-served by overstating projections, which then require even more extensive resources and more dramatic land use and transportation changes than would be required with more realistic estimates," Williams wrote.

The city's challenge to ABAG is expected to intensify in the coming months as the regional agencies proceed with choosing a preferred "Sustainable Community Strategy" alternative for the Bay Area. The regional agencies plan to perform an environmental analysis on the strategic document over the coming year and adopt it by April 2013.

Williams noted that under regional projections, all three scenarios would achieve roughly the same greenhouse gas reductions (about 8 percent for the first two, slightly below 8 percent for the "outward growth scenario"). But the implications of which scenario is chosen would be very significant for cities like Palo Alto.

"We're probably going to make the point that doing all this heavy concentration is a burden to cities like Palo Alto and it's unrealistic," Williams said. "At the same time, the increment of improvement in greenhouse-gas emissions isn't that significant and that perhaps it would be better to leave some flexibility for the cities to do something else to reduce greenhouse gases."

Continued testing on PG&E's Line 132 is expected to cause traffic along Alma Street to be redirected for 10 days starting Jan. 18, City of Palo Alto Utilities spokeswoman Debra Katz said Tuesday morning (Jan. 17).

The work involves checking the outside casing surrounding the pipe for flaws. The 55-mile Line 132, which runs from Milpitas to South San Francisco, is the one involved in the San Bruno explosion and fire. The California Public Utilities Commission required PG&E to use hydrostatic (water pressure) testing to find leaks in the pipeline after the explosion.

Between September and November 2011, PG&E performed the tests on sections of the Line 132 pipe, which runs through Palo Alto. The pipe has been fully tested and was returned to full service in December, the city noted on its pipeline update page.

Related story: PG&E repairs leak in Palo Alto pipeline (Nov. 11, 2011)

The surrounding casing inspection would not cause impacts to service or any odors, Katz said. The main effect will be on commuters traveling southbound on Alma from Jan. 18 through Jan. 28. The work will be done between Alma and the Caltrain railroad tracks, just before the intersection with Oregon Expressway, Katz said.

Katz said commuters should consider taking alternate routes.

PG&E has three main transmission pipelines that traverse Palo Alto -- Lines 101, 109 and 132. Line 132 is the only one of the three pipelines required to be tested in PG&E's current hydrostatic testing project, the city noted.

Line 109 runs along Middlefield Road from Mountain View but then turns up East Charleston/Arastradero Road, continuing north along Foothill Expressway. It has had about two thirds of its length replaced in recent years and is believed to have been hydrostatically tested already but paper record verification of that is still underway, according to PG&E.

Originally installed portions of this pipeline -- running along Charleston between Alma and Middlefield -- are scheduled for replacement sometime between 2012 and 2014. That schedule is currently being prepared, according to PG&E.

Line 101 runs roughly parallel to Highway 101. All of the Palo Alto portions of this pipeline have been replaced since the requirement for hydrostatic testing was in place and there are validated records of passing this test, according to PG&E.

PG&E intends to install a permanent "in the pipeline inspection device" launching station on East Bayshore Road that will allow future regular, ongoing inspections. Construction of this device could start as early as summer of 2012.