After Fairfax County voters choose a president, vice president and members of Congress this November, they will be asked to approve $325 million in bond sales to improve and expand parks, libraries and mental health centers and launch long-ignored road projects.

The separate bond measures will be the only local issue on the Nov. 2 ballot in the absence of county or state races. Fairfax officials hope to draw voters to the bond issues by sending them a detailed brochure on the proposed spending next month.

The bonds are a blueprint of the county's capital needs. Construction of parks, libraries and roads as well as schools boomed in the 1960s and '70s. Now the population has surged again and become more diverse, and the county has expanded services to meet it. County officials want to renovate some public buildings and parks and in other cases build new ones.

The county limits its bond sales to $200 million a year to maintain its top AAA bond rating. So if voters approved the projects on the ballot, the bonds would not all be sold this year, or even next year, but as the projects are designed. The money must be used within 10 years. Bonds are like any debt. The interest and principal are paid off over the years and become part of the county budget.

Much of the county's bond money has been devoted in recent years to school construction and renovation, which are on the ballot every other year. This year, other areas are begging for attention.

"This year we're catching up," said Supervisor Sharon S. Bulova (D-Braddock), chairman of the county board's budget committee. "Although it's not nearly the amount we've invested in schools, we're addressing a diverse array of services county residents rely upon."

The lineup that will appear on the ballot is $32.5 million for human service facilities, $52.5 million for library construction and renovation, $75 million for county and regional parks and $165 million for transportation improvements.

An act of frustration put road projects on the list this year for the first time in a decade. With the state pulling back resources and the defeat of a sales tax increase earmarked for transportation projects in 2002, the county board decided to seek local money for several road projects that have been languishing on Virginia's to-do list.

The first library bond since 1989 would fund construction of two buildings and the expansion of four others in a system that now receives 5 million visits a year. Branches built 40 years ago cannot accommodate the printers, computer terminals, community rooms and sheer number of books the system needs now, officials said.

And where libraries used to be for reading, they function now as community centers, playing host to story hours, lectures, puppet shows and book groups for teenagers.

"Sometimes we have to turn kids away," library spokesman Lois Kirpatrick said.

The Park Authority hopes to spend its bond money to build athletic fields, update playgrounds and trails and acquire open space, a priority in recent years.

Spokesman Judy Pedersen said the Park Authority was lobbied heavily by a variety of park users, from soccer coaches to horse owners, to expand services. Choosing projects was grueling. The authority wants to accommodate parkgoers' changing needs. For example, few existing parks can handle large family groups that often stay all day to picnic.

Among the specific items included in the bond issue are:

* $5 million for pedestrian improvements.

* $50 million for road projects, including improvements to Route 29 at Gallows Road and expanded parking at the Burke Centre Virginia Railway Express station.

* New libraries in Oakton and Burke.

* Renovations to the Mount Vernon and Woodburn community mental health centers.

* $12 million to acquire parkland.

* $8.5 million to build athletic fields.

Supervisor Sharon S. Bulova (D-Braddock), chairman of the budget committee, said of the bond measure: "This year we're catching up."