When Utahns fill the family sedan with their favorite brand of gasoline, 19 cents of every dollar they shell out goes to repair and maintain highways.

At least that's what taxpayers have been told.The truth of the matter is that more than $30 million a year is being siphoned away from the Transportation Fund to pay for an assortment of non-highway proj-ects, including the Utah Highway Patrol, the state Tax Commission and the Driver License Division.

Now, with a backlog of badly needed highway projects totaling hundreds of millions of dollars, lawmakers are saying a cap on the diversions is long overdue.

"We have a moral commitment to the citizens of this state that if they pay a tax for road maintenance then it should be used for road maintenance. We must honor the very premise of a user tax," said Rep. Frank Knowlton, R-Layton.

According to recent transportation studies, more than $1 billion worth of high-priority highway projects need to be completed over the next five years, though anticipated revenues total only about $500 million.

While highway planners estimate a $500 million-plus shortfall, the state has since 1980 quietly siphoned almost $175 million away from those highway proj-ects.

Knowlton has sponsored a bill that would limit the amount of money that could be siphoned from the state Transportation Fund, and Wednesday the bill received unanimous approval by the Revenue and Taxation Committee.

It also received rousing support from an unlikely alliance of the Utah Taxpayers Association, the League of Cities and Towns, the Utah Association of Counties, the construction industry and the petroleum industry.

"The fact that the Utah Taxpayers Association is in agreement with the Utah League of Cities and Towns on anything is reason enough to pass this bill," joked Howard Stephenson, Utah Taxpayers Association.

Under the provisions of HB44, the maximum that could be diverted from the fund would be $25 million in 1990, $20 million in 1991, and $15 million in 1992.

In the current budget year, some $33 million is being diverted from the highway fund - $8 million above the recommended cap.

The public has traditionally supported gasoline taxes because they are user taxes. Those who use the roads more pay more, "and the tax is not burdensome on those who don't," said Knowlton.

But the Transportation Fund has found itself subject by budget-balancing raids by lawmakers faced with lean revenues in other budgets. What lawmakers did not fully consider was that 25 percent of those diverted gasoline tax revenues was supposed to go to cities and counties to maintain local roads.

This year, the amount of money lost to local governments is about $8 million.

"That kind of money is very important to us," said David Spatafore, Utah League of Cities and Towns, adding that local entities find it difficult, if not impossible, to make up the shortfall.

The bill now goes to House floor for debate.