DETROIT — A new study concludes that traffic on the near-century old Ambassador Bridge will remain fairly steady over the next 25 years.

The study, conducted by engineering consultants Halcrow Group Ltd. for the Detroit International Bridge Co. found the Ambassador’s traffic would experience "a small decline" through 2035, according to the Detroit News.

Bridge traffic was reportedly up at the Ambassador in the first four months of 2010, but is significantly lower (-43%) than a decade ago.

The study used employment and auto industry forecasts to project traffic volumes.

Commercial truck traffic is expected to grow some 2 percent in that period, which, bridge officials argue may not be enough to sustain current international crossings as well as a planned government controlled bridge a few kilometers downriver.

Ambassador owner Matty Moroun and his top executives have argued that decreasing traffic numbers doesn’t support the need for a new bridge at the trade gateway. he says the Detroit River International Crossing (DRIC), if built, would hurt his company as well as Detroit/Windsor Tunnel and the Blue Water Bridge in Sarnia-Port Huron.

Michigan lawmakers could vote this week whether to continue supporting DRIC and accept a $550 million offer from Ottawa to pay for the state’s share of the bridge. The legislature has until June 1 to decide.

Moroun, meanwhile, has already summoned his lawyers and says he will fight the DRIC in court.