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Inside the Fourth Bore

Traveling through the Caldecott Tunnel is now easier, thanks to the brand-new fourth bore. Here’s the scoop on this high-tech project and the people who make the tunnel work.


Karl Nielsen

What’s the Worst That Could Happen?

Through the Years
Young Artists

By the Numbers

Get Ready to Roll

Watching the Tunnel Transform



Karl Nielsen

What’s the Worst That Could Happen?

A look at the tunnel’s state-of-the-art safety systems.
By Stacey Kennelly

On a recent brisk fall afternoon, Byron Lim moved loosely inside the fourth bore, which was nearly complete. Clad in construction garb, he pointed out safety features: state-of-the-art lights, massive jet fans buzzing overhead, and seven passages that connect the fourth bore to the third.

Behind him trailed two-dozen men and women from the Oakland Fire Department, eager to explore. These firefighters are a few of hundreds of first responders on both sides of the tunnel who were touring the bore before it opens, as they will be the ones to rescue motorists if a traffic accident, fire, or earthquake traps people inside.

The Fourth Bore Project has been decades in the making, and it has come with its challenges, including securing $420 million in funding, and tunneling more than a mile through rock in the Berkeley hills. The bore will eliminate traffic for reverse commute drivers so four lanes of motorists don’t have to merge into only one two-lane bore, backing up traffic for miles.

For engineers, including Lim, one of the trickiest aspects of building the fourth bore has been piecing together a plan to rescue people in case of an emergency, and building a cutting-edge safety system. Top of mind is making sure they have safer systems than they did in 1982, when an accident started a fire in the third bore, killing seven people.

That’s where Lim, a Caltrans employee, comes in. More than a year ago, Lim started working with the Moraga Orinda Fire District, Oakland Fire Department, California Highway Patrol, State Fire Marshal, and other agencies to create an emergency response plan.

“Everyone had an idea of what to put in the tunnel,” Lim says, “but we needed to put it together.”

Lim knows how the latest technology can make tunnels safer. He worked on two other high-profile Caltrans projects: the Tom Lantos Tunnels, which opened near the coast in Pacifica in March, and the Doyle Drive tunnel in San Francisco’s Presidio neighborhood.

In a compact, simple building above the west-side opening of the tunnel sits the new operations building, the “nerve center” of the Caldecott. Here, in a small room holding a network of equipment and cords, computer fans hum loudly. In a larger room next door, two operators will monitor real-time systems that give information about environmental conditions, including heat and air quality. They’ll also watch video feeds.

Operators will be on the lookout for different scenarios, from low-level incidents, like an animal in the tunnel, to high-level incidents, like a fire that would require evacuations. Depending on the situation, they will notify first responders, post messages on digital signs to warn drivers, and lower new railroad-style gates in front of the third and fourth bores to stop cars from entering.

“If something really happens, the system is programmed to implement appropriate protocols,” Lim says. “At the same time, we need humans here, so they can use their judgment, too.”

Engineers have tried to back up the system wherever possible: The entire mainframe is duplicated in a separate building nearby, in case the main building were to burn down, and a secondary power supply exists on the other side of the hill. These back-up systems are especially important because the tunnel must reopen to emergency traffic within 72 hours of a major earthquake.

The new building is evidence of how far technology has come. When the first three bores were built, in the 1930s and ’60s, there were no carbon monoxide monitors, heat sensors, or cameras inside. These things have been added, but only the fourth bore has the technology to detect heat.

“We are giving the fire department the tools we didn’t have in 1982,” Lim says.


Through the Years

1860s: A tunnel connecting Lafayette to Oakland is first considered.
Late 1870s: The Oakland and Contra Costa Tunnel Company builds the Kennedy Toll Road. Digging begins, but the company runs out of money.
1870s to early 1900s: Most travelers go over the steep Berkeley hills in horse-drawn carriages, but accidents are frequent. Others take the long way, through Richmond.
1890s: A new tunnel is financed by Contra Costa and Alameda counties, and private citizens.
1903: A tunnel opens that is dark, narrow, and one-way only.
1915: The tunnel is widened for automobiles, but trucks struggle with the steep approach.
1927: An Oakland engineer declares the tunnel to be “quite safe” but admits the tunnel posts are moving.
1929: Contra Costa and Alameda counties and the city of Oakland form a commission to build a two-bore tunnel.
1934: Construction begins on the new two-bore tunnel.
1937: The two-bore tunnel opens, coinciding with the opening of the Bay Bridge. For the first time, residents can commute from Contra Costa to San Francisco.
Late 1950s: The state plans to build a third bore to accommodate the more than 50,000 cars driving through the tunnel each day.
1960: The third bore project breaks ground. Bores one and two receive upgrades. “Pop-up” lane control is installed to change the direction of the middle bore to ease traffic during commute hours.
1964: Bore three opens.
1982: An accident causes a massive fire in the tunnel, killing seven motorists. The tragedy sparks reforms in tunnel safety.
2004: Regional Measure 2 and Contra Costa Transportation Authority Measure J are passed, contributing $50 million and $120.6 million to the Fourth Bore Project, respectively.
2009: The American Recovery and Reinvestment Act contributes $194.3 million to the project.
2010: The Fourth Bore Project breaks ground.
2011: After months of tunneling from the east and west, the tunnel breaks through.
November 2013: The fourth bore opens.


Karl Nielsen

Young Artists

Local kids designed the new bore’s medallions.
By Peter Crooks

On your next drive through the fourth bore, make sure to glance up just before you enter. You’ll see a series of art deco–styled medallions above the tunnel’s entrance designed by six students—three from Alameda County and three from Contra Costa—who won a Caltrans competition.

Walnut Creek resident Penelope Watson drew a deer grazing in the East Bay hills, with San Francisco in the background. “I have been drawing all my life, but I didn’t expect to win,” says Penelope, 15, a sophomore at Las Lomas High.

Another winner, Chaya Tong of Lafayette, learned about the competition from a school newsletter. Chaya asked her mother to take her to the library to learn about art deco. From there, she incorporated the region’s history.

Karl Nielsen“I knew Contra Costa has an important agricultural history, so I drew grains of wheat against rolling hills,” says Chaya, 10, a fifth-grader at Springhill Elementary.

Both Penelope and Chaya are thrilled that their art will be seen by millions of motorists. “I’m really proud to know it will still be up there for a long time, even after I’m really old,” Chaya says.


By the Numbers

2: Number of stories in the tunnel’s new operations building.
3: Number of geologic formations excavated during digging (Sobrante, Claremont, and Orinda).
7: Number of passages between bores three and four to evacuate drivers in the event of an emergency.
7: Number of motorists who died in the 1982 fire in bore three.
12: Width, in feet, of each lane in the fourth bore.
19: Number of jet fans installed to control temperature and push out smoke.
41: Width, in feet, of bore four.
72: Hours in which the tunnel must reopen to emergency traffic after a major earthquake.
75: Number of years of the fourth bore’s design life.
120.6: Amount in millions raised by Measure J, which was approved by Contra Costa County voters in 2004.
194.3: Millions of dollars funded by the American Recovery and Reinvestment Act.
417: Millions of dollars spent on the project.


Get Ready to Roll

Five reasons we’re excited about the fourth bore. 
By Peter Crooks

01: Express Lane to Entertainment
There’s nothing worse than being psyched to go to a Warriors game or a concert at the Fox Theater in Oakland, and then getting stuck in the single lane snarl leading up to the Caldecott. OK, a BART strike is worse.

Still, two westbound bores at all times means that stop-and-crawl delay you would have experienced driving to the December 21 game against the Lakers is a thing of the past, and you can get to the Head and the Heart concert on December 5 without a headache.

02: Fewer Runaway Stagecoach Accidents
Next time you’re stuck in tunnel traffic and some driver forces a merge ahead of you, put your middle finger down, take a deep breath, and remember that all four bores keep you from having to clamber over the Berkeley hills in a buggy to get from one side to the other.

In the 1880s, it took more than two hours to get from Lafayette to Oakland by stagecoach—and there were frequent accidents when the carriages would lose control on the steep, twisty roads. Your Prius is practically a spaceship in comparison.

03: Still No Toll
Do you know how much it costs to drive through New York’s Holland Tunnel these days? Thirteen bucks! And you don’t even get a spectacular view of the Bay (or Mount Diablo, if you’re eastbound) on your way out.

Driving through the Caldecott just costs you the gas in your tank, although that wasn’t always the plan. In the late 1870s, the Oakland and Contra Costa Tunnel Company tried building a toll road through the hillside, but ran out of money after digging a few hundred feet.

04: Meltdown Money = Bore Bucks
The years-in-waiting fourth bore received an infusion of $194 million in President Obama’s Recovery Act to finally move the project forward. So if there hadn’t been a catastrophic economic meltdown in 2008, we might still be trying to merge into one bore. Glass half full!

05: More Holiday Shoppers in Walnut Creek
Bore four will bring more folks from west of Caldecott to Walnut Creek for holiday shopping. That means more cars searching for parking spots, more people in line for gingerbread lattes in Starbucks, and … oh man, the freakin’ Apple Store. Attention Berkeley and Oakland readers: The Caldecott’s fourth bore is being closed for repairs. Happy Holidays!


Noah Berger

Watching the Tunnel Transform

How one East Bay photographer documented the project from start to finish.
By Stacey Kennelly

Berkeley photographer Karl Nielsen has been drawn to construction sites since he was in college, when he would hop fences at night to photograph buildings in progress. So when long-awaited plans to build a fourth bore for the Caldecott Tunnel became a reality, Nielsen knew he was the photographer to document the job.

It took a little convincing, but Municipal Transportation Agency officials allowed Nielsen to shoot inside the site shortly after construction started. He was invited back after they saw his photographs. So far, Nielsen has snapped roughly 5,000 shots of the equipment, geology, and people behind the project, and two of his photos have won prestigious awards. Diablo asked Nielsen about his experience.

How did you feel when you first entered the tunnel?
When they were first starting out, it was a very intense environment. Equipment moved quickly, and it was very noisy, to the point where you couldn’t hear somebody talking to you. But it was a thrilling place to be, because it’s an unusual situation, and an unusual type of construction: The building of tunnels and large bridges doesn’t happen very often.

What surprised you about the process?
When they broke through from the east side to the west side, it was really chaotic, uncivilized, and unruly. There was a lag between when I watched them break through, and when I went back. When I did, they had put gravel down on the roadway, and they had dug out more of the tunnel. It seemed like an actual public utility—very civilized, very organized, and no longer like the Wild West. That was a big change.

Describe the moment when workers broke through.
It was in the evening, and there was a small group of engineers and politicians present for the event. It was kind of cool to see the final couple inches of the Caldecott connect between the two sides. As soon as the heavy machine broke through, workers stopped for 30 to 45 minutes so they could make measurements. Then, they’d break through some more, and stop and take measurements again. It was slow, but it was exciting.

Shortly after the breakthrough, I got a shot of one worker taking a picture of it on his cell phone. It was a very human moment, and in the photo, you can tell the workers are impressed by the work they’ve done—that it’s not something they see every day. The photo I took later won an award in Communication Arts.

What was the most interesting part of the experience?
The workers, especially the miners who were involved with the project in the first half. There were two crews: one on the east side, and one on the west side.

The equipment they work with is not light—big jackhammers, heavy welding equipment. If they want to change out a piece of the boring equipment, it’s a big, heavy metal thing that has to be physically lifted and bolted on.

They told me stories about their families; stories about guys having heart attacks at other construction sites, and then taking aspirin and coming back to the job. These guys are tough as nails, and they don’t know anything but to work hard.

What about construction appeals to you?
I think big construction projects are probably as close as you can get to being in a war zone, without actually being in a war zone.

Visually, they’re incredible: You have really rough characters doing extremely hard work in challenging situations. Often, they’re high up in the sky, or down under the ground.

I originally went to school for engineering. When shooting, I’ll ask the site engineers way more questions than they’d expect me to ask. They say, “Why do you want to know that?” It helps me connect with people.

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