Detroit and Riverside/San Bernardino counties would seem to have little in common beyond inclusion in the United States.

The Motown image: Grimy, rundown, gloomy, losing its key industry -- cars.

The inland counties' image: Sunny, new, smoggy, car-saturated.

But it turns out the two areas share a distinction both would rather avoid: In November, they were tied for the top jobless rate among the 50 metropolitan areas in the United States with populations of 1 million or more. Preliminary figures for December indicate the jobless rates in both places rose further -- Riverside County to 10.1 percent; the Detroit metropolitan area to 10.6 percent.

"We're bordering on a depression," says John Husing, the inland area's top economist and principal of Redlands-based Economy & Politics Inc.

Just as the decline in Detroit is linked directly to the fortunes of the car industry, the economic fates of Riverside and San Bernardino counties is tied to construction.

For Riverside County, joining Detroit in jobless rankings testifies to the depth and difficulty of the area recession.

Husing notes that while Congress is sending multibillion-dollar bailouts to the car industry, little direct relief is expected from Washington for what ails Riverside and San Bernardino counties. Moreover, he said, the southwest sector of the county probably is faring worse than the two-county averages, because much of the housing and commercial building boom was centered in the area.

In 2005, permits for residential and commercial construction in the two counties totaled $12.5 billion. Last year, that dropped to $3.9 billion. That collapse of investment flowing into the area strangled the economy in the same way that the decline in sales of American cars punished Detroit.

"To get out of this, something has to fill that (investment) hole," said Husing.

Long-term, Husing and other economists say the inland counties must boost education levels to draw research, development and technology jobs such as those in San Diego and Orange counties.

"We are in the worst possible position," said Mason Gaffney, economics professor at UC Riverside. The reason, he said, is because the construction in the area has been focused on housing and warehousing businesses, which generate relatively few jobs.

For the inland area economy to build an economic base beyond construction, Gaffney says some revision -- if not an outright repeal -- of Proposition 13 will be required.

Prop. 13 limits residential property tax increases, but Gaffney and other economists say the effect has been to shift the tax burden to businesses.

Michigan passed a similar law in 1995, and Gaffney says it has helped turn the state into an economic "basket case."

So while Michigan hitches its economic salvation hopes on enough federal money to resurrect the car-building industry, Riverside and San Bernardino counties' economic challenge is a bit simpler.

"Our fundamental competitive advantage is dirt," said Husing. He added, however, that he doesn't see any resumption of building on that vacant land until 2012 when the last of the adjustable and interest-only mortgages issued during the boom years resets.

Contact staff writer Jeff Rowe at (951) 676-4315, Ext. 2621, or jrowe@californian.com