Officials OK Testing for Roadway Tunnel

Riverside and Orange county transportation officials moved forward Friday with testing on one of the more radical alternatives for bringing relief to the traffic-swamped Riverside Freeway -- an 11-mile tunnel through the Santa Ana Mountains.

Transportation boards from the two counties met Friday in Riverside and approved taking soil samples in the hills to determine whether the tunnel is a feasible alternative to the freeway, the main artery linking Riverside and Orange counties.

Although expensive, the tunnel, which could cost from $5 billion to $7 billion, hasn’t been ruled out by officials who seek to make the best use of the region’s transportation system, said Jeff Miller, a Corona councilman and chairman of a regional transportation committee.

“The tunnel is among a number of projects being worked on right now to alleviate traffic on the 91 Freeway,” said Miller. He said building more lanes by widening or double-decking the freeway remains a planning priority in addition to the proposed tunnel.

The freeway is regarded as one of the most congested corridors in Southern California with 320,000 daily drivers. By 2025, the number is expected to reach 450,000 a day.

By comparison, the Costa Mesa Freeway has 307,000 daily drivers and is expected to have 339,000 a day by 2025.

The most congested stretch of the Riverside Freeway is the Corona bottleneck, eight miles between I-15 in Riverside County and the Orange County line. At peak hours, the average speed is less than 14 mph.

Transportation engineers will seek permits from federal environmental agencies to bore five holes within the Cleveland National Forest to test for rock formations and groundwater levels, among other things. The tests will help determine whether the area can support a tunnel.

In addition, information will be shared with the Metropolitan Water District of Southern California, which is conducting soil tests for a possible pipeline in the same area, said H. Tony Rahimian, a transportation consultant.

Funding for the work will come from $15.8 million that Congress allocated for tests in April.

The decision to drill the test holes comes amid growing support for the tunnel by Riverside County officials seeking to ease traffic congestion and increasing opposition by southern Orange County officials, who fear that a tunnel would fill their neighborhoods with more traffic.

Several south Orange County cities and the area’s largest landowner, the Irvine Co., have formally opposed the tunnel.

The proposed tunnel would connect Interstate 15 in Corona to the Foothill-Eastern tollway in Irvine.

Riverside County Supervisor John F. Tavaglione, who sits on the Riverside County Transportation Commission, said something must be done soon because frustration is mounting among his constituents.

Tavaglione wanted to ensure that the five holes would be enough for engineers to make a determination.

“What if after waiting two years for permits and getting results, it’s determined that we need to do more borings?” he asked experts. He received no guarantees that they would be enough.

Tavaglione and other officials urged engineers and transportation staff to work to cut red tape in getting the permits for the tests, and in seeking federal help for construction funding from Congress.

Tavaglione became frustrated when told that a Caltrans project to add an eastbound auxiliary lane for one mile along the 91 Freeway wouldn’t be done for an additional 18 months.

“We need to get things expedited,” he said. “Eighteen months for restriping? This time frame is unacceptable.”

A Caltrans spokesman said the agency would try to advance the project. It includes moving the median to create room for another lane from State Route 71 to Serfas Club Drive and restriping the lanes.

No funds to build a tunnel have been allocated. Environmental and feasibility studies are expected to take at least 10 years, and if construction is approved and the project funded, it could be built by 2023.

Improvements to the Riverside Freeway will remain a priority, transportation officials said.

More than $1.5 billion to improve the freeway has been included in a sales tax measure in Riverside County and in the extension of Measure M, Orange County’s half-cent-on-the-dollar sales tax used for road and transit projects. Approved by voters in 1990, Measure M expires in 2011 and is up for renewal Nov. 7. The extension would continue the tax until 2041.

david.reyes@latimes.com