If you’re in a hurry and you want to do a quick century ride in the South Bay that avoids traffic, there’s a great way to go about it. Just follow the trails and this route.
The ride starts anywhere along the Guadalupe River Trail, preferably north of Taylor Street where it’s a straight shot to Alviso. The trail allows you to ride non-stop under all roads and freeways, passing the San Jose airport on the way. It’s unpaved north of Highway 880. One of these days government money will become available and we’ll have a paved trail [paved as of May 2013]. Be sure to switch to the east side of the river at Airport Parkway.
Just past Trimble Road on the river shoreline, a mastodon was discovered in 2005. The bones were removed and now you can’t tell where they excavated. The dirt trail is smooth, although there is some heavy gravel on the Tasman Drive underpass. It can also be muddy here from seepage [while paved there are still flooding issues at low spots].
Go left onto Gold Street, where the trail ends. After a half mile, turn right on the Gold Street connector at the light. After a few tenths you pick up the trail and bridge over to paved San Tomas Aquino trail for some more uninterrupted riding all the way to Central Expressway. I’m pretty sure you can get onto the expressway here. The trail opens in June at this point. Otherwise you go left at Scott and then right at the light to wind around to the Central Expressway.
Central doesn’t have many lights. Take the Middlefield Road exit and continue on Middlefield to Rengstorff. Turn right and take the 101 overpass, then left at the light onto Garcia. Ride past Intuit and Google offices over to the Bayshore Road, which parallels Highway 101. Turn right on Bayshore and continue to Embarcadero Road, turning right at the light. Take an immediate left at the next light onto Geng Road, which takes you past a recreation area and yet another path.
Follow this path for about a half -mile, crossing a slough at the first bridge and continue east until the paved trail ends. Turn left on Runnymede Street, right on Pulgas, left on Bay Road. Continue to the light and turn right on University Avenue. This takes you to the Dumbarton Bridge path, where a 100-foot climb greets you.
Dumbarton Bridge Path
It’s non-stop for several miles to the Dumbarton Bridge toll booths, where you turn left onto signed and paved Quarry Trail. Cross over the toll booths and you’ll be greeted by a giant hole in the ground. The quarry is so deep there’s a below-sea-level lake.
Quarry Trail is good dirt for a mile or so over to the paved path around Coyote Hills Regional Park. Use caution here as there is a fair amount of foot and bike traffic at all hours. It’s a beautiful view in the spring with flowers in bloom.
This trail joins with the Alameda Creek Trail at a short, steep connector trail. Once again, you’ve got nine miles of non-stop riding on the trail. It has a fair amount of traffic, so this isn’t a place for racing.
The trail finally ends at Niles Canyon Road, Highway 84. If you started from home and rode five miles or so to Guadalupe River Trail you’ll be at about 50 miles. I rode Hwy 84 for a few miles. I don’t ride this road unless I have to. It has no shoulder in places and two narrow bridges.
Return the way you came. If you left early, you won’t have much wind to contend with. It’s mostly a tailwind going home, with some sidewind on Dumbarton Bridge.
I can’t think of a better long and flat ride avoiding traffic in the crowded Bay Area.