Q I can't believe that Caltrans wants $76 million to paint some carpool lanes on Interstate 680 through Walnut Creek. No wonder this state is broke.

Craig Bender

Walnut Creek

A Caltrans says widening the freeway from South Main to just south of Rudgear Road in Walnut Creek entails considerably more work than perhaps immediately meets the eye.

This is a 5.5-mile stretch of freeway, and in addition to widening and re-striping, the project includes relocating utilities as well as sound and retaining walls, installing metering systems at several ramps, upgrading the median barrier between Rudgear and Geary and installing metal guardrails and crash cushions.

Another often forgotten cost is doing this work while keeping traffic flowing. This requires traffic management and a lot of night work to reduce impacts to commuters. In addition, work will take place in confined spaces that slow productivity.

By comparison, adding auxiliary lanes on 101 for 3.5 miles in Mountain View will cost $72 million. Bottom line: Road fixes involve more than painting a few lines.

Q Does Caltrans have plans to add any signage explaining to drivers approaching the Caldecott Tunnel about the upcoming divide in the highway? For drivers unfamiliar with the road split, there is no warning telling drivers which tunnel goes where.

We heard about this confusion from some of our European friends who said they didn't see any road signs about the split and they questioned if they should be in tunnel left or tunnel right. Maybe this is why I have seen a few drivers at the last minute cross over the center divider to head into the other tunnel at the last minute.

Robert McGillis

Oakland

A No signs are needed, says Caltrans. With the opening of the fourth bore late last year, each lane on Highway 24 now has a dedicated lane in the tunnel, making directional signs not necessary. Caltrans will install a permanent concrete barrier between bores 2 and 3, because there is no longer a need to shift the direction of traffic in bore 2 to accommodate peak traffic.

Q OK, I get the part about the necessity of curving the fourth bore of the Caldecott Tunnel to accommodate soil conditions, geology, etc. But Ivy-the-Caltrans-Caldecott-Know-It-All's statement that a straight line from each end of the tunnel would have increased the length of the tunnel by about 40 percent violates what most of us learned at some point or other, that the shortest distance between two points is a straight line. Why would a straight tunnel have been 40 percent longer than the curved tunnel built?

Richard Milward

Concord

A To eliminate the curves in the tunnel, engineers would have had to go back past the curve on each end of the tunnel (east of Fish Ranch Road in Orinda and to the Caldecott lane offramp in Oakland). This would have made the tunnel a straight line, but it would have been longer and would have cost a lot more.

Q I saw your column and the references to electric car driver habits. As a Leaf driver, I like to hyper-mile with the best of them. Sometimes this means driving the speed limit or even a little slower when it's safe to do so. For me, this generally means driving in the right lane on freeways and making frequent use of pullouts on two-lane roads so as not to impede Californians' God-given right to speed.

I also love my white carpool stickers. When I do make use of them, I fully understand that safety and civility dictate that I drive like a bat out of hell along with the rest of the carpoolers. And darn it all, I even turn on my headlights when it's appropriate.

Jeff Frankel

Alameda

A Some drivers are amazing.

Q Have you seen the new ramp from Capitol Expressway west to 101 north? The entry lane from Capitol is only a 40-foot single lane into the ramp. When you get in, you get two lanes for 30 feet, then a 90-degree turn into a three-lane ramp. It is very difficult for drivers to get on the freeway. There is land on the right of the three-lane ramp that is left unused! Any comments?

Ananthu Krishnamoorthy

San Jose

A This is a new Caltrans design for safety reasons. Old urban interchanges are sometimes being reconfigured to safely accommodate bicyclists, pedestrians and motorists. When engineers were designing the interchange, they received numerous complaints about drivers not yielding to bikes and pedestrians.

For that reason, sidewalks were widened and the geometry was changed to reduce speeds, giving motorists more time to react to pedestrians or bicyclists.

Q I noticed that two new galvanized steel sign poles have been place on Willow Road at either end of the stretch between 101 and Bayfront Expressway. What for (hopefully to ease traffic on that section of road)?

Don Manoogian

Danville

A Those are called trail blazer signs and will be used to divert traffic to backup routes if there are problems on 101 or the Dumbarton Bridge.

Q I have a question about the carpool lane between Decoto Road/Highway 84 west and the Dumbarton Bridge toll booths. My work hours are flexible and I usually leave home at 10 a.m.

But the carpool lane in this stretch is only on until 10 a.m. and I never see any single-person cars in that lane, even when the other lanes are jammed with traffic. It does lead to a FasTrak toll lane, and since I have FasTrak I expect it shouldn't be a problem. But I am really confused. Is it OK to drive on the carpool lane after 10 a.m.?

Fiona G.

Fremont

A Only if you have FasTrak. Carpool hours end at 10 a.m. After that the lane is reserved for FasTrak users.

Q A couple of months ago I emailed a request to Caltrans regarding its lack of maintenance of the bike path on the Dumbarton Bridge. They do not sweep it regularly and the path is full of glass and sand, with no clear space for bikes to safely pass in opposite directions. Would you contact Caltrans and suggest they start cleaning the bike path, at least weekly?

Jerry Edwards

Menlo Park

A A cleanup will take place Friday. Caltrans does this twice a month, on the 2nd and 4th Friday of the month. Go to www.dot.ca.gov/hq/maint/msrsubmit/ to make a maintenance request.

Look for Gary Richards at Facebook.com/mr.roadshow, follow him at Twitter.com/mrroadshow or contact him at mrroadshow@mercurynews.com.