It's bad enough that more and more cars keep pouring onto the freeway as Riverside County's growth boom rages on. But anymore it's not just swelling ranks of sport utility vehicles, compact sedans and vans. More and more it's big trucks.

Construction and freight trucks are everywhere. And transportation officials say commuters better get used to them because a whole lot more are coming.

Hasan Ikhrata, planning and policy director for the Southern California Association of Governments, the nation's largest regional planning agency, said Friday that trucks used to make up 3 percent of vehicles traveling the highways of the Los Angeles metropolitan region, whose long arms reach to Riverside County. That was in 1990.

Today, the heavy trucks account for about 6 percent of traffic, Ikhrata said, and the trend isn't expected to slow. By 2020, he said, one in every 10 vehicles on the freeway will be a big rig.

Commercial trucks will be especially noticeable on Highway 60, which follows an east-west track through northern Riverside County. There, one in three vehicles will be a truck, association forecasts show. Truck traffic averages 47,000 vehicles a day now on the 60 freeway and it is projected to hit 110,000 in 2020, Ikhrata said.

Most of the truck traffic on the Inland Empire's east-west routes, which include Highway 91 through Corona and Interstate 10 in Ontario, are coming from or returning to the ports of Los Angeles and Long Beach, Ikhrata said. And traffic growth will be heavily influenced by the anticipated tripling of cargo shipments to the ports between now and 2020, he said.

Already, the twin ports on the Pacific make up the world's third busiest port complex after Hong Kong and Singapore, according to the ports' Web sites.

Ron Roberts, association president and a Temecula councilman, said the cargo expansion is being driven by the booming economies of China and other Asian countries. Asia is making products that used to be manufactured all over the United States —— and delivering them through the ports of Los Angeles and Long Beach.

As a result, increasingly more products are being shipped by truck to distant domestic markets through Southern California, he said.

And the first stop for many of those products is one of the new Inland Empire warehouse and distribution centers, said John Husing, a regional economist based in Redlands.

"A lack of space in the coastal counties, combined with an enormous increase in international trade, is driving the distribution industry to increase in size," Husing said. "A lot of the facilities are being built inland. And that's what's driving a lot of the 18-wheel traffic we are seeing."

There's no stopping it

Truck traffic on north-south routes, namely Interstates 15 and 215, is influenced more by Corona's sand-and-gravel mines, growing retail markets in Riverside and San Diego counties, and the housing boom that is heating up demand for a whole array of construction materials, Roberts said.

Riverside County Supervisor John Tavaglione said a lot of the increase is inevitable because, as the population continues to grow, so will the need for more goods and services —— and for more trucks to deliver those.

Riverside is on track to become California's fourth most populous county and is rapidly approaching the 2 million mark. By next decade's end, there will be close to 3 million people in the county, demographers say.

The disproportionate growth in truck traffic is particularly troubling for transportation planners, Roberts said, because area freeways are becoming severely congested and just one 18-wheeler takes up about four cars' worth of space.

"We have a lot of heavy equipment being moved between jobs," Roberts said. "That sure ties up traffic. And when they crash, they tie up more than one lane, too. We are very concerned about the increase in the number of trucks going through Riverside County. There is just not enough room for them."

However, officials say the region has little choice but to make room for the trucks, because the freight containers on wheels are already here and the health of the region's economy hinges on their ability to continue rolling to market. And officials say projected traffic increases are not numbers pulled out of the sky but realistic predictions of how many trucks will be roaming Southern California's highways in the near future.

"They are coming, no question about it," Ikhrata said. "And we must accommodate them."

Because the monster vehicles are coming, government agencies are studying a variety of strategies designed to speed their travel through the region and separate them from frustrated commuters.

Truck lanes and truck routes

The most ambitious is a Southern California Association of Governments proposal for a four-lane, $6.2 billion road that would be designed exclusively for commercial trucks and be financed by truck tolls, Ikhrata said. The limited-access route would connect the ports with a major distribution center in the Victorville-Barstow area, following the 710, 60 and 15 freeways.

"Once they got on, there wouldn't be a lot of exits on the way to their distribution centers," Roberts said.

In Riverside County, officials are wrestling with how to accommodate swelling truck traffic in the county's unincorporated communities, after Tavaglione brought the issue to the Board of Supervisors' attention several months ago. A report is due back to the board on March 15.

Tavaglione said preliminary ideas include designating truck routes in order to keep 18-wheelers out of neighborhoods and business districts, and restricting parking to certain busy streets so trucks don't clog narrow, residential lanes. The county supervisor said the latter idea stems from Moreno Valley's recent move to allow parking only along Alessandro Boulevard, a strategy he says is working.

As far as freeways in Southwest Riverside County are concerned, Roberts said he does not believe exclusive lanes are needed. Instead, he said, transportation officials should concentrate efforts on widening Interstates 15 and 215 so that there is plenty of room for truckers and commuters to spread out.

When voters countywide agreed in November 2002 to extend a sales tax of a half penny on the dollar for transportation, I-15 and I-215 widening were on the list of projects to be funded. But because the tax extension doesn't take effect until 2009, the money won't begin to flow for a few years and it will be well into next decade before those projects are completed, officials say.

Contact staff writer Dave Downey at (951) 676-4315, Ext. 2616, or ddowney@californian.com.