Montgomery County Executive Douglas M. Duncan yesterday proposed a construction budget that is the product of a booming economy, flowing over with money for schools, roads and a variety of costly projects that suddenly seem affordable.

The $1.7 billion capital budget represents a 14 percent increase from the last six-year plan proposed two years ago. The increase is possible, Duncan (D) and his budget officials say, because of soaring tax revenue and glowing financial forecasts that forced the county executive to make few hard choices.

"Clearly this budget continues the emphasis on education we have seen for so many years, but a much bigger portion of it this year will go to transportation," Duncan said. "Those are the two biggest issues facing the county."

The County Council must approve the capital budget by the end of May after holding a series of public hearings. Most members received the plan with enthusiasm yesterday, raising only faint alarms about the fiscal assumptions it is built on.

"It must be understood that much of this proposal is predicated on certain assumptions regarding state aid and a continued robust economy," Council President Michael L. Subin (D-At Large) said in a statement. "Should either or both of these assumptions not materialize, the council will have to make some very difficult cuts."

Much of the new spending would be devoted to Montgomery's public school system, which would receive a 9.3 percent funding increase. Duncan included 92 percent of the Board of Education's $670.7 million request, which would speed school modernization projects and allow construction of 202 classrooms and three new schools.

Duncan did not include money for the board's early childhood development initiative or money for elementary school gymnasiums. Amid general praise for Duncan's budget, school board officials also pledged to continue lobbying for those projects.

The budget proposal also includes a 9 percent increase for transportation projects, including nearly $63 million for the Montrose Parkway in North Bethesda. It has money for four new recreation centers, two new libraries, and 20 new ball fields.

The proposal would also include $15 million to begin a conservation program known as Legacy 2000, which Planning Board Chairman William Hussmann proposed to buy and preserve unique swaths of land. Hussmann asked for more than four times that amount.

Duncan also included $50 million to buy a public-safety radio system that has been a priority of Police Chief Charles A. Moose. The budget includes money for two new upcounty fire stations and a police station serving Montgomery Village and Gaithersburg.

"This budget does an awful lot," Duncan said.