Gov. James S. Gilmore III (R) tonight declared his adamant opposition to legislation that could allow voters across Northern Virginia to say whether their counties and cities should assess local income taxes to finance transportation projects.

Gilmore's announcement was consistent with his long-standing opposition to new taxes, but it dashed the hopes of some suburban lawmakers who had been following the delicate negotiations about the measure between J. Kenneth Klinge, of Alexandria, an old Gilmore friend and transportation expert, and M. Boyd Marcus Jr., the governor's chief of staff.

With Klinge as their go-between, key members of the Northern Virginia delegation to the General Assembly were hopeful that Gilmore would support a bill sponsored by Del. James M. Scott (D-Fairfax). Scott's bill would revise an existing local income tax law to make it more palatable to governments in Arlington, Fairfax, Loudoun and Prince William counties, as well as Alexandria and other municipalities.

But Gilmore's visceral opposition to any new taxes effectively killed the Klinge-Marcus talks.

"Although existing law permits selected localities to conduct referendums to levy local taxes for transportation, I do not support expanding the current law, as proposed legislation would do," Gilmore said in a statement.

Gilmore press secretary Mark A. Miner added: "The governor is opposed to any legislation that would ultimately end up as a tax increase for the people of Virginia."

Instead, the governor in his statement reiterated his support for his own $2.5 billion transportation program, a spending plan that includes no new taxes, but which assembly leaders are criticizing as gravely flawed.

At the very moment Gilmore's office issued his statement, Shirley J. Ybarra, his transportation secretary, was across Capitol Square enduring her latest round of withering questioning from legislators skeptical about the timetable and funding for highway improvements in their home districts.

Del. J. Paul Councill Jr. (D-Southampton), 78, one of the most senior members of the House, complained to Ybarra that a road project back home that had been delayed for 10 years did not appear on Gilmore's $590 million list of 90 accelerated projects.

"I'll never vote for this unless I can get that in here," Councill said.

Ybarra, who in recent days has faced questioning even tougher than Councill's, defended Gilmore's program as an innovative response to the traffic congestion that vexes regions such as Northern Virginia, which stands to get $138 million to speed up 10 projects.

Scott and other lawmakers were disheartened by Gilmore's announcement, but they held out a sliver of hope that they could rework their proposal, which would allow a local levy of up to 1 percent on Virginia taxable income. An estimated $430 million would be raised annually if all the eligible jurisdictions approved the new tax.

Gilmore said the Scott bill would expand the 1989 law giving Virginia's fastest growing counties their taxing authority. The bill permits some of those new dollars to go for education, as well as transportation.

Scott's measure also removed an old "sunset" provision that made the law expire eventually. That was an effort to help localities raise even more long-term money through bonds, he said.

Fairfax City Mayor John Mason, who heads a regional transportation panel along with Klinge, said that he was disappointed with Gilmore's statement and that it could be a serious blow to the region's ability to fund massive transit and road projects. "It does close down one of the options," Mason said of Gilmore's comments. "It's unfortunate that this could result in an inadequate debate on the alternatives. It's a serious blow if no other significant form of funding is identified."

Mason said that he and other local leaders support Scott's amendments to the income tax law and that they would be willing to put the issue to a local referendum if the legislature decided that imposing a local income tax was the best way to solve the area's gridlock.

"Most of us would be comfortable imposing the question to voters, to the residents, 'Do you want this form of funding?' " he said.

Scott said tonight that his measure "was a technical correction to a flawed bill."

"It gave voters an opportunity to have localities pitch in, while recognizing that the state and federal governments must be the principal source for transportation funding," he said.

Scott said his disappointment was all the more acute given the assembly's reaction to the Gilmore program, pieces of which are already tattered in a legislative session less than three weeks old.

"We don't want to leave this legislature without a package," Scott said.

Klinge, reached by telephone tonight, declined to comment on Gilmore's announcement.

Staff writer Michael D. Shear contributed to this report.