KTVU Channel 2 News has learned that an ongoing multi-million dollar Caltrans program placing critical traffic sensors under Bay Area freeways is largely broken.

That means traffic data that shows up on everything from freeway signs you see while driving to your smart phone may be meaningless.

What's more, Caltrans has failed to disclose the collapse of the project we uncovered, even though billions of dollars for freeway construction and planning relies heavily on the faulty data.

Caltrans collects the data using three principle methods: specialized loops of wire under roads, wireless sensors replacing the old loops and FasTrak transponders in vehicles.

But there are far too few FasTrak devices to accurately measure traffic flows, especially outside of Alameda County.

And now KTVU has learned the other two technologies have largely failed.

The cost to taxpayers: $60 to 80 million.

One top Bay Area transportation official, who asked not to be named because he has to regularly work with top Caltrans officials, calls it "a scandal."

Moreover, Caltrans has known the data are seriously faulty in key Bay Area locations, but has also failed to report it to the paying public, agencies that depend on the critical information and even the state legislature it is accountable to.

Specifically, internal Caltrans documents we obtained show among the biggest failures are:

• Except for an insignificant stretch of road on highway 101 in Marin County, every sensor on that freeway between Windsor in Sonoma County and San Rafael in Marin is dead.
• On the Peninsula, the entire 43-mile stretch of Interstate 280 between King Street in San Francisco and Magdalena Avenue in Los Altos Hills is dark.
• In the East Bay, none of the sensors are working on Highway 24 in the critical area between Acalanes Road in Lafayette and the Caldecott Tunnel.
• And the entire 72-mile stretch of Interstate 680 all the way from I-80 in the north to 101 in the south has no working sensors.

Some of the few key arterials where the sensors are working reasonably well are Highway 101 on the Peninsula and both Interstate 880 and I-580 in the East Bay.

Collecting the information is a vital task for Caltrans. Not only do drivers depend on traffic times delivered to freeway signs, apps on smart phones and computers, but all traffic reports on the news as well.

What's more, a law voted in by Californians in 2006 requires it.

And billions of dollars for California freeway construction and federal grant applications are heavily dependent on the numbers the sensors deliver.

Caltrans engineers acknowledged many of the problems we uncovered, although they downplayed their severity.

"Right now we have a fairly high failure rate," said Sean Nozzari, the Caltrans engineer in charge of collecting the data for the Bay Area.

"We've looked at our system and we've identified as many as 50 to 100 things that could go wrong with the system," he added. "It could be a faulty detector card, it could be a bad camera, it could be a bad wire."

Nevertheless, Nozzari says he stands by the travel data Caltrans provides.

"There probably are holes in the system but I can tell you these are very, very useful information that we put out for travelers," he asserted.

The Berkeley-based company that makes the wireless sensors also stands by its product.

The "reliability rate is about 99 percent," said Ray Schreiber, the marketing director at Sensys.

He added that Caltrans may be doing something as simple as not flipping on a switch.

"You actually have to have the modem turned on," Schreiber quipped.

Schreiber also said Sensys has heard nothing from Caltrans about any problems, even as the 5-year warranties tick away.

"Our door's open," Schreiber said. "Come tell us what you need help with."

Caltrans counters it is working with Sensys. Caltrans officials also declare they don't have the money to repair the system.

In fact, Caltrans says it will be two to five years before it can fix it. That's at least one year past the warranties on the newest road sensors.

The powerful chairman of the State Senate Transportation Committee was unhappy hearing the news.

"Nothing is more irritating to me than hearing about these things from you -- from the press, said State Sen. Mark DeSaulnier, D-Walnut Creek. “We should hear about it from Caltrans."

"I can't tell you how important this is," he remarked. "The application of this technology is the future of transportation for people. In California we should be cutting edge. We shouldn't be doing things like this."