COEUR d'ALENE - En route to northern Alberta, two "megaload" tractor-trailers will soon be passing through Coeur d'Alene.

And despite assurances from oil company spokesmen, local environmentalists are concerned about accidents and delays.

On Friday the Idaho Transportation Department issued a pair of oversized-load permits that will allow Imperial Oil/ExxonMobil to transport large oil equipment on U.S. Highway 95 and Interstate 90.

Carried on specialized trailers, the megaloads will travel from Lewiston to the Kearl Oil Sands Project near Fort McMurray, Alberta. The trucks will pass through Moscow, Coeur d'Alene and the Silver Valley.

"There's a number of modules (loads) currently at the port of Lewiston, which were shipped in late 2010," said Imperial Oil spokesman Pius Rolheiser. "They're prefabricated modules that are manufactured in South Korea. It's a variety of different components."

The cargo includes metal piping, industrial equipment and material for building a plant. No hazardous materials will be transported, he said.

Both ITD permits have an effective date of June 27, so the oil company cannot haul any loads until that date or later. A transport schedule has not been set.

"There are still a number of details that need to be worked out," Rolheiser said.

One load is 208 feet long, 23.2 feet wide and weighs 410,300 pounds, including the tractor-trailer, according to ITD spokesman Adam Rush. It will stretch across both lanes of Highway 95.

The second load is much smaller, measuring 14 feet wide, 80.7 feet long and weighing 76,100 pounds. Both shipments are just over 13 feet tall.

Rolling about 30-35 mph, the megaloads will travel primarily at night, between 10 p.m. and 5:30 a.m. They will be escorted by pilot cars and Idaho State Police.

On Highway 95, motorists can pass the megaloads at turnouts or wide spots in the road, Rush said. The interstate is wide enough to allow for conventional passing.

Under ITD regulations, large trucks are not allowed to delay traffic for more than 15 minutes.

"(The loads are) moving when the number of vehicles on the highway are as low as possible," Rush said.

A trip from Lewiston to the Montana line will take about three nights.

Oversized loads are common on state highways, Rush said. Idaho truckers haul bulky silos, long wind turbines and prefabricated homes.

"We have had over-legal loads travel on all our state highways," Rush said. "We move a variety of equipment and goods."

Imperial Oil/Exxon Mobile's original route was along U.S. 12, a serpentine highway through pristine mountain forests. But environmental groups and residents near U.S. 12 opposed the megaloads, and permits were delayed.

The Highway 95 corridor was the company's next best option.

Megaloads entering Coeur d'Alene will have to negotiate several sharp turns. After crossing the Spokane River, trucks will make a hard left onto Lincoln Way, following Highway 95 northward through town.

Another right turn leads to the on-ramp for eastbound I-90.

"I think there are a couple of really tight corners that are going to end up being problematic," said Terry Harris, executive director of Kootenai Environmental Alliance. "I think as they pass through town it's going to be a problem for neighborhoods nearby."

Harris said the 200-foot megaloads could disrupt traffic and cause delays. Moreover, the loads are servicing a major oil project that Harris strongly opposes.

"It is going to cause all sorts of environmental problems," he said, including carbon emissions and the destruction of Alberta's landscape.

Mommoet, a contract transport company, will haul the heavy megaloads up to the Canadian oil sands. Its high-tech trailers boast hydraulic weight distribution, breaking and steering systems.

Some megaload trailers have up to 14 axles, with each axle carrying eight tires.

"(Mommoet) has extensive experience in moving large equipment," Rolheiser said. "The bottom line is to move them safely and effectively, while complying with the 15-minute traffic rule."

A self-described "one-man banana stand," Bill Rodgers operates his own lowbed service in Post Falls. He often hauls big loads on local roadways, and was happy to hear that ITD had issued two megaload permits.

"They're going to help North Idaho's economy quite a bit, I believe," Rodgers said. "Those (truck crews) will need places to stay, and they'll be spending money for whatever they need when they go through."

Rodgers has carried cargo as wide as 16 feet. Driving a megaload, he said, is a time-consuming and careful process.

Weaving through Coeur d'Alene shouldn't be a problem, though, "because the big (trucks) have people steering them. They have hydraulic steering for two or three different locations," Rodgers said. "They're pretty sophisticated."

Harris remains dubious. KEA will monitor the big rigs as they travel down Coeur d'Alene's streets.

"We'll see what happens," he said. "They're huge. They're two lanes wide and the equivalent of four semis long."