County roads are about to get a $1.9 million shot in the arm, but it may be too little too late.

With the final numbers in for the 2008 county budget on Tuesday, officials found they had underestimated county income by about $2.1 million — and quickly routed most of the money for ailing roads.

The money will come as the Napa County Public Works department hires an engineer to develop a plan to deal with a massive projected imbalance in the road budget. The cost of maintaining county roads in recent times has far exceeded the department’s funds.

Nearly half of all county roads are listed in fair or worse than fair condition, according to a recent county report, leaving places like the Circle Oaks subdivision with streets that mostly resemble the back of an alligator, causing wear and tear on car tires.

An Aug. 28 presentation to the Napa County Board of Supervisors showed the road budget — about $7 million — needs at least another $11.7 million per year — or $293 million over 25 years — in order to properly maintain roads.

Some roads, like Highway 29, are state routes maintained by Caltrans. But critical arteries including Silverado Trail and streets in rural subdivisions like Circle Oaks are maintained with county money.

The problem is so daunting some supervisors off-handedly suggested letting some infrequently used roads go back to gravel.

This could be frustrating to taxpayers, but it is a symptom of a fiscal storm in which gas taxes and other road revenue remain stagnant while construction costs climb and roads continue to deteriorate.

Napa County has among the worst roads in the Bay Area and is one of only two counties that don’t have a local sales tax devoted to funding road maintenance. Voters rejected that idea in 2006, but transportation planners are testing the waters to bring a tax proposal back in 2008 because they say the need is great.

In another bit of bad news, the county is still waiting on $5 million in reimbursement for flood-related damage to roads and other infrastructure from the Federal Emergency Management Agency, having for the better part of a year been drawn into the complex world of FEMA appeals.

Napa County Supervisor Bill Dodd said Tuesday that the road budget is so bad, even a half-cent local sales tax — of which 80 percent would be devoted to road maintenance — would only pay for half of what is necessary.

Public Works Director Bob Peterson said with the imbalance in the road budget, the county may not be able to respond effectively to damage during floods and severe storms.

“FEMA is not quick to reimburse us,” he said.

One possible Band-Aid is to cut corners, relying whenever possible on cheaper materials that don’t last as long as higher quality rubberized asphalt.

Other ways to cut costs if need be? County staff is thinking about placing roadkill removal and litter pickup on the endangered list.

Then there’s another idea: Sacramento. The county could join up with other local governments and lobby the Legislature and governor for increased gas tax revenues tied to inflation.

But at the Aug. 28 supervisors meeting, Dodd said that’s a last resort.

“The whole county needs to understand the state and the feds are not going to bail us out,” he said. “This is our liability.”