ORINDA -- A peculiar Bay Area traffic ritual is about to end after a half-century run: the daily repositioning of the Caldecott Tunnel pop-up lane markers by the cone guys.
Twice a day, the cone crew boldly trucks into live freeway traffic to raise and lower plastic cones -- actually, they're shaped more like cylinders -- that reverse the traffic flow in the two-lane middle bore.
The 2-foot-high yellow plastic pop-ups have been used since 1964. And, for just as long, Highway 24 motorists have cursed or rejoiced at the sight of the cone crew. Drivers losing two lanes of tunnel in their direction are unhappy. The lucky motorists who gain use of the middle tunnel cheer.
But the cone age will end soon -- rendered as obsolete as the buggy whip.
When the $417 million Caldecott fourth bore opens the weekend of Nov. 16, the two-lane middle bore won't switch directions anymore. The tunnel will have two permanent two-lane bores in each direction.
Kiss the cones goodbye.
"There is a little nostalgia ending a job done the same way with the same equipment for nearly 50 years," said Tony Padilla, a Caltrans tunnel and bore supervisor at the Caldecott. "I'm not sad, though. This is a big improvement, making things easier for motorists."
A co-worker is blunter.
"I can't wait for the pop-ups to end," Ron Jakubs said. "I never really liked going out on a freeway with cars and trucks whizzing by you at 65 mph."
The use of pneumatically powered cones at the Caldecott to reverse directions between Orinda and Oakland is the only operation of its kind on a Bay Area freeway, Caltrans officials said.
Golden Gate Bridge workers switch the flow of some lanes, but they place traffic markers manually.
Installed along with the Caldecott's third bore in 1964, the plastic cones come in sets of about seven that are screwed into 12 different embedded metal rails that are raised or lowered one at a time.
Activating a series of cone lines to pop up or down switches the direction in the middle bore to go with the prevailing traffic flow -- westbound in the morning, eastbound in the afternoon. Crews also place or remove a motorized metal barrier to prevent motorists from driving the wrong way into a tunnel.
But popping up cones is not something done in the comfort of an office. A cone cowboy with a remote control must drive in the fast lane to get close enough to a series of freeway signal boxes to activate them. An escort truck follows with a flashing message sign.
"It can be dangerous," Padilla said, "so you have a sequence you follow. If the control box doesn't work, you use a key. If the key doesn't work, then someone in a truck must manually set out the cones."
Last week, Padilla and Jakubs teamed up for the cone switch just before noon to turn the middle bore flow east toward Orinda.
Driving the lead truck on westbound Highway 24, Padilla carefully steered his truck into the fast lane, slowed near a signal box, and pressed a remote control. The first seven cones popped up.
"The magic box works," Padilla said and smiled.
He repeated the process to pop up other cones. When one set failed to budge, Padilla left the truck and used a key to lift them.
Padilla appeared calm and confident despite the loud rush of vehicles, vibration and wind gusts.
After raising the cones, the two then did it in reverse, lowering cones on the other side of the tunnel.
When one cone failed to descend, Jakubs hopped out of his truck, unscrewed it and placed it where a subsequent crew would repair it.
Weekday lane changes are done twice a day -- from 11 a.m. to noon, and from 3 to 4 a.m. There are no weekend switches because traffic is too unpredictable.
Padilla said motorists are frustrated when they lose two lanes and have to weave through congestion.
"We can't please everyone," Padilla said. "We try to please the majority. That's why the lane change is done."
Caltrans says no tunnel workers will lose their jobs because there is plenty to do with the opening.
"We are losing the lane change," Padilla said, "but we're gaining a bore."
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.