Freeway Traffic Projections Skyrocket : Transportation: Even with present freeway and road expansion plans, traffic from Riverside County could overload the system by 2010.

More than 400,000 vehicles a day may be using the Riverside Freeway into Orange County by the year 2010, a 50% increase over previous county forecasts, officials said Monday.

Traffic volume on the Orange Freeway is also expected to be 50% greater than county officials had previously projected, with about 306,000 daily trips expected 20 years from now.

County Environmental Management Agency Director Ernie Schneider called the new traffic forecasts alarming, pointing out that such staggering volumes of traffic would overload the system of roads and freeways now being planned for Orange County.

During an hourlong press conference at the Hall of Administration, Schneider and other county officials labeled the new projections a “warning signal” for local elected leaders and residents alike.

“What’s happening is that we’re being impacted by areas that we have no control over,” Schneider said, pointing in particular to the hordes of motorists who each day drive from Riverside County to jobs in Orange County. “This really raises the flag of regionalism.”

But some officials contacted after the press conference said the new forecasts should come as little surprise. For several years, they noted, officials of the Southern California Assn. of Governments have been voicing similar dire predictions about the growth of traffic in Orange County. But county traffic prognosticators have insisted that the SCAG figures were exaggerated.

Stan Oftelie, executive director of the Orange County Transportation Commission, said that county traffic planners “should be embarrassed” by the new numbers for the two freeways.

“They have finally come around to SCAG’s numbers,” Oftelie said. “But the big question is, what’s to be done about it.”

Supervisor Don R. Roth agreed that the county’s previous projections were “ludicrous,” but he said he found little solace in assessing blame.

“The spinoff of all this is an increase from month to month in the number of people using side streets,” Roth said. “It’s scary as hell. That’s why we have to look at alternatives such as monorails and people-movers, ideas that will get people out of the automobile.”

The new traffic projections for the Riverside and Orange freeways spring from an upgraded computer study just completed by county transportation planners. The new projections incorporate much more data than previous studies performed by Orange County.

A 1985 study by the county predicted that 237,000 vehicles would use the Riverside Freeway daily in 2010. The new computer study puts the number at 400,000; about 188,000 vehicles now use the freeway each day.

The 1985 study found that traffic on the Orange Freeway would rise from the current 174,000 vehicles a day to 208,000 by 2010. But the new study forecasts that traffic volume on the freeway will reach 306,000 cars and trucks a day.

The mammoth new traffic volumes reflect a continuing trend--an increase in the number of jobs throughout central Orange County, while Riverside and San Bernardino counties remain a burgeoning cluster of bedroom communities exporting workers.

In particular, Riverside and Orange counties have become economically dependent on one another, underlining the need for adequate transportation systems linking the two areas, officials said during the press conference.