On Prince William County's Route 1, where traffic can be unbearable and the changing demographics are evident in Spanish replacing English on business signs, the battle between Del. Jeffrey M. Frederick (R-Prince William) and longtime county Supervisor Hilda M. Barg (D-Woodbridge) has grown heated.

The candidates for the 52nd District House seat have honed in on campaign issues of transportation and illegal immigration as residents complain about long commutes and day laborers waiting for work outside a 7-Eleven on Route 1.

The race has become significant for Democrats who think they have a chance to steal the seat held by Republicans in recent years. Despite losing the presidential bid, Sen. John F. Kerry (D-Ma.) had a strong showing in the district. Democrats are hoping those Democratic-leaning voters who also cast their ballots for Barg for supervisor will support her for state delegate, said Rick Coplen, chairman of the Prince William County Democratic Committee.

Meanwhile, Frederick is trying to hold on to his seat, which he won in 2003 after besting longtime incumbent John A. "Jack" Rollison III in a primary. A relative newcomer, Frederick moved to the county in 2000.

The Frederick-Barg race is one of the most competitive in Virginia and will be influenced by party affiliation and the gubernatorial contest between Timothy M. Kaine (D) and Jerry W. Kilgore (R), said Larry J. Sabato, director of the Center for Politics at the University of Virginia.

The district's tally for governor will likely match the votes for state delegate, he said. "Part of it will be coattails of the gubernatorial election. . . . In the end, this race will be decided by party. How many Kilgore-Barg voters are there going to be? How many Kaine-Frederick voters will there be? There'll be a handful," Sabato said.

Barg, a retired businesswoman who owned two shoes stores and a beauty salon, is one of only two Democrats on the Board of County Supervisors. She calls herself a moderate who can cross party lines.

Frederick, who recalled that his slogan for college senate was "Vote for Jeff Frederick, the guy with two first names," said he knocks on doors for votes all over the district. "We don't discriminate between who we think is a Republican and who we think is a Democrat," he said.

Frederick and Barg are at pains to appear tough on illegal immigration.

Frederick has voted against in-state tuition for undocumented immigrants and asked Gov. Mark R. Warner (D) to declare a state of emergency to address the immigration issue in Virginia. He said he has been so outspoken about illegal immigration that Hispanics have questioned his Colombian heritage. Frederick recalled that a participant in an online chat once asked what was the "Spanish word for Uncle Tom," referring to his views.

His wife has been harassed at a shopping center frequented by Hispanics because of his opposition to undocumented immigrants, he said.

After two dozen Hispanic men were arrested and charged with loitering in front of a 7-Eleven on Route 1 last year, Barg assembled a task force to address the issue of day laborers. Months later, the task force recommended the county contribute $150,000 to operate a day-labor center. Neither Barg nor anyone else on the Board of County Supervisors would place the recommendation on the board's agenda.

Barg's approval as a supervisor of developments throughout the district have contributed to traffic and other problems, Frederick said. He questioned her receipt of campaign contributions from developers.

"Mrs. Barg has been in office for 18 years. Is Woodbridge any better off than 18 years ago? Woodbridge is a lot worse," he said. "You can't stop growth. You have to manage it."

Barg said she has not been influenced by developers' contributions and agreed that growth must be managed. She said she has tried to vote for subdivisions that improve the look of Route 1, long known for its aging strip malls and older subdivisions.

"The growth that has come has been smart growth," she said. She pointed to Belmont Bay, the subdivision where Frederick lives.