Q I commute from Walnut Creek to San Francisco in a vanpool. Mornings are not a problem. We leave early and have the Bay Bridge carpool lane. Our trip home is the problem. The gridlock through San Francisco and the ridiculous tiny carpool entrance to the bridge may be unfixable, but Highway 24 has become unbearable. There are simply too many cars with too many single passengers. When the fourth bore of the Caldecott Tunnel opens, is there any thought of designating a carpool lane? Is anyone paying attention? It's rarely mentioned on traffic reports.

Maria Hetherton

Clayton

A I hear this complaint often. Alas, there are no plans to add a carpool lane through the tunnel, but extending the carpool lane to the bridge deserves serious consideration.

Eastbound at  the Caldecott Tunnel.
Eastbound at the Caldecott Tunnel. (Bay Area News Group)

Q Do you know when they will finally open up the ramp from Park Presidio to the Marina district in San Francisco? It looks like work is done, but that ramp just sits there closed, forcing people onto the detour and messing up traffic.

Brian Yee

San Francisco

A Patience is needed. Lots of it. This ramp will not open until 2016. Right now all traffic has to use a single tunnel and there is not enough merging distance from the ramp onto the main road to allow traffic to merge safely. When work ends, the existing bridge will carry only southbound traffic, creating enough space for traffic to safely merge from the connector ramp to south 101.


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Q Does Caltrans have plans for improving the Interstate 80 to I-780 ramp in Vallejo? It's a real mess.

Danny Richards

Benicia

A There are no imminent plans to alter the existing I-780/I-80 interchange or the ramp to I-80 from Magazine Street. The state and the Solano Transportation Authority are looking at long-term improvements through Vallejo. This would likely mean adding a carpool lane on I-80 and redesigning several other ramps through Vallejo.

Q The Tully Road interchange is almost completed at Highway 101, and it looks like they have put down many rolls of grass sod. It looks great but I thought the goal was to plant water-saving vegetation. What's going on? ... Who thought that nice green lawns were a good idea? Now they will need crews out each week to mow the new lawns. ... I appreciate the beautiful job of landscaping at Tully/101 with green lawns and trees. However, anyone that has a lawn knows how much maintenance they require, not to mention the amount of water to keep it green. Why would Caltrans, with a drought imminent, put lawns at this interchange?

Peggy Thompson, Don Axtell, Robert Schubert and many more

A It's not exactly what it seems. Caltrans has installed what it calls a "mow-free" native grass blend. While regular sod needs to be mowed weekly, native sod can be mowed seasonally or annually and supplemental irrigation can be turned off after the sod is established in one to three years.

This version protects water quality by reducing the amount of herbicide needed and protecting bare soil and sediment from entering storm drains. Native grasses are adapted to California's diverse climate and various soil types don't require fertilizer to thrive. And the native grass sod forms an instant thick mat that chokes out weeds.

It also uses 50 percent less water, Caltrans says, and its deep roots enable it to survive our dry seasons.

Look for Gary Richards at Facebook.com/mr.roadshow or contact him at mrroadshow@mercurynews.com or 408-920-5335.