COEUR d'ALENE - Diamond Cup organizers are warning of traffic congestion heading into the race's return this weekend.

One big change in preparation for the inaugural return: Most of East Coeur d'Alene Lake Drive will be reduced to one lane of traffic. The road is the main thoroughfare getting to Silver Beach, where the race course will be set up.

The modification will run Thursday through Sunday to allow organizers to place about one mile's worth of bleachers in the lane of traffic closest to the water. The other, westbound lane, will remain open for traffic but flaggers will be stationed at Potlatch Hill Road and just west of Sunnyside Road to control one-way traffic flow.

The Centennial Trail will also remain open, but will be diverted next to the single lane of vehicular traffic, organizers said.

Kootenai County Sheriff's Office Capt. Andy Boyle said anyone looking to travel to Higgens Point or the boat launch at the eastern end of the dead-end Coeur d'Alene Lake Drive is asked to use Sunnyside Road.

Sunnyside Road connects to the eastern side of Tony's restaurant, and can be accessed via Mullan Trail and Interstate 90.

"As far as traffic, this is new to us, so we don't know" how it's going to go, Boyle said.

The bulk of the hydroplane racing activities are slated from 8 a.m. to 5 p.m. Friday, Saturday and Sunday. Friday's events are primarily test and exhibition runs, and spectators won't be charged to watch, said Herb Huseland, Diamond Cup volunteer.

But in an effort to reduce traffic congestion, spectators are encouraged to use free bus services from the Kootenai County Fairgrounds as well as the downtown shuttle services to get to the course, the KCSO said in a press release.

About 15 to 20 buses will be running from the fairgrounds Saturday and Sunday.

Parking, however, won't be available at the race course, but a bicycle corral will be set up across from the Beachouse restaurant, manned by security guards, to encourage people to pedal to the races to ease traffic congestion.

The bike corral will be set up next to the beer garden going up for the event.

One other device spectators are encouraged to bring: A radio.

The sound system being set up along the course isn't as extensive as organizers had originally hoped because the system exceeded its budgeted estimate, so some spectators might not be able to hear the announcer's blow-by-blow at the event.

But an FM station, 90.5, will broadcast the event, so anyone with a radio can tune in regardless of where they sit in relation to the race course's speakers, said Doug Miller, Diamond Cup organizer. It will have a four-mile reach.

"We're ecstatic," he said. "We're going to get boats wet, that's the main thing."

The weekend will include professional wakeboard exhibitions all three days, Miller added.

From now through the Labor Day weekend, numerous course buoys and log booms will be moved into the area for the races, and boaters are encouraged to use caution when traversing the area around the course, the KCSO said.

The office will also man increased patrols through the Labor Day weekend to ensure the safety of all residents and guests to Kootenai County, it said in a press release.

It's the first time sanctioned hydroplane racing has returned to Coeur d'Alene since the 1960s.

"We sincerely appreciate the public's cooperation and look forward to an enjoyable weekend," the KCSO said.