The goo holding together Battle Creek''s streets could put the city''s long-term roadwork plan into a sticky situation.

Overall construction costs are up by about 15 percent compared to recent years, with a big jump in liquid asphalt rates, City Engineer Chris Dopp said. The petroleum-derived mixer, used to bond together gravel, has skyrocketed in price by 120 percent during the past decade, national statistics show.

That growing cost, among others, could make city officials rein in road repair.

"Probably 2008 is when you''ll see things really start to get affected," Dopp said.

City planners work from a five-year road improvement plan, and have not changed their immediate course. Some projects, however, have not been priced for 2007, including a 2.5-mile, three-year reconstruction of Riverside Drive. If prices stay high, the city might use 2008 funding to finish off this year''s projects, Dopp said.

Asphalt coats about 94 percent of U.S. roads and highways, according to the National Asphalt Pavement Association, a Maryland-based trade organization.

Liquid asphalt is a key ingredient in the substance — it''s the glue holding together gravel and other substances. While liquid asphalt only makes up about 6 percent of the mix in Battle Creek roads, that small amount costs a fortune.

This summer''s upcoming road resurfacing work in Battle Creek covers 6.63 miles and includes pieces of Territorial Road and Capital Avenue Southwest, Dopp said. About 708 tons of liquid asphalt will be used.

Based on national figures provided by the trade publication Engineering News-Record, that comes to $199,000. In 1998, the cost would have been $91,000.

Liquid asphalt has leapt from $128.33 per ton in 1998 to $281.65 this year, according to Engineering News-Record. The largest jump in a decade came this year. Prices are up 27 percent compared with the same period in 2006, when they were at $221.88.

"Keep in mind that most construction materials have experienced large price escalation since 2004, although that is tapering off now," said Timothy Grogan, who monitors prices for the New York-based News-Record.

Asphalt costs often go up with oil costs because both are made from petroleum, said Margaret Cervarich, a spokeswoman for the pavement association. The expense could level off soon, but no one''s banking on it.

"It''s really hard to say," Cervarich said. "I will say when the price of oil goes up, the prices of all construction goes up."

Whether Battle Creek will change direction on roadwork remains to be seen.

"The policy question that lay ahead is whether we want to commit to covering the same mile of streets as we have in the past or commit a dollar amount," Assistant to the City Manager Michelle Reen said.