By Car in California Wine Country

Five major roads cut through the Napa and Sonoma valleys. U.S. 101 and Routes 12 and 121 travel through Sonoma County. Route 29 heads north from Napa. The 25-mi Silverado Trail, which runs parallel to Route 29 north from Napa to Calistoga, is Napa Valley's more scenic, less-crowded alternative to Route 29.

Remember, if you're wine-tasting, either select a designated driver or be very careful of your wine intake. (When you're taking just a sip or two of any given wine, it can be hard to keep track of how much you're drinking.) Also, keep in mind that you'll likely be sharing the road with cyclists; keep a close eye on the shoulder.

When calculating the time it will take you to drive between Napa and Sonoma valleys, remember that the Mayacamas Mountains are between the two. If it's not too far out of your way, you might want to travel between the two valleys along Highway 12/121 to the south, or along Highway 128 to the north, to avoid the slow, winding drive on the Oakville Grade, which connects Oakville, in Napa, and Glen Ellen, in Sonoma.

In April 2007, a section of Interstate 580 collapsed onto Interstate 80 in Oakland. At this writing, repairs were anticipated to last at least several months and traffic was extremely snarled. If you're driving to Wine Country from the East Bay, check on the status of these roads and alternate routes.

From San Francisco to Napa: Cross the Golden Gate Bridge, then go north on U.S. 101. Next go east on Route 37 toward Vallejo, then north on Route 121, also called the Carneros Highway. Turn left (north) when Route 121 runs into Route 29. This should take about 1½ hours when traffic is light.

From San Francisco to Sonoma: Cross the Golden Gate Bridge, then go north on U.S. 101, east on Route 37 toward Vallejo, and north on Route 121, aka the Carneros Highway. When you reach Route 12, take it north. If you're going to any of the Sonoma County destinations north of the valley, take the U.S. 101 all the way north through Santa Rosa to Healdsburg. This should take about an hour, not counting substantial traffic.

From Berkeley and other East Bay towns: Take Interstate 80 north to Route 37 west, then on to Route 29 north. To head up the Napa Valley, continue on Route 29; to reach Sonoma County, turn off Route 29 onto Route 121 heading north. Getting from Berkeley to Napa will take at least 45 minutes, from Berkeley to Sonoma at least an hour.