Yvonne Piane, a housewife from Missoula, heard a radio announcer remind listeners of Montana's new daytime speed limits moments before a police officer pulled her over for speeding on U.S. Highway 93 on the Flathead Indian Reservation.

"I totally agree with it," Piane said. "But I think it's going to take a little bit of time to slow people down."

Traffic on this highway, Montana's deadliest, seemed remarkably sedate today compared with holiday weekends since 1995, when Congress revoked the national speed limit. Montana then reverted to a law that did not specify daytime speeds.

Last winter, after the Montana Supreme Court declared the law too vague, the state legislature agreed on numerical limits that took effect 15 minutes before dawn today. The speed signs have been up for more than a month, and notices have been posted at rest stops: Don't exceed 75 mph on the interstates, and stay below 70 on secondary roads. The only exception is the 65 mph limit the length of U.S. Highway 93, from the Canadian border to Idaho.

Patti Marnon, a waitress at the Bison Inn Cafe here, is relieved that there is a daytime limit. "With no speed limits, it seemed like everything was out of control," she said. "All-out rage was going in every direction. There was always somebody coming dead at you when they were passing, then swerving back in at the last moment. I've driven into the ditch several times to avoid accidents."

But some drivers, such as Dorothy Klinkenbeard, owner of Joe's Smoke Ring near Evaro Hill, will miss the old ways.

"I drove 90 to 95 on the interstate," she said. "Otherwise, it felt like I was crawling. I'd try to slow down, but the next thing I know I'd be right back up there. It seemed safe. Today, I had to set my cruise control at 65." She seemed to be the exception among residents who live along this narrow, heavily traveled road--the main thoroughfare from Missoula to Glacier National Park. Many early-morning coffee drinkers at the Bison Inn Cafe called the new limits too high.

"Speed kills," said retired schoolteacher Max Johnson. "You can hardly pull out onto the highway nowadays. Plus, people can't react at high speeds. It's just nuts."

There will be no grace period to educate motorists about the new limits, said Col. Craig Reap of the Montana Highway Patrol: "We will enforce the law."

Denny Orr, an officer with the Confederated Salish and Kootenai Tribes on this reservation, said he will be stopping people who exceed the limit by 5 mph. "Speeds in Montana have been frustrating me," he said. "I'll be pretty stringent."

Fines range from $20--for driving up to 10 mph over the limit--to $100--for barreling in excess of 31 mph over.

While the public perception was that Montana had no speed limit, the standard had always been "reasonable and prudent," giving police discretion to consider weather, road and vehicle conditions. There were numerical speed limits for trucks and nighttime limits for all vehicles. Because highway deaths did not increase at first, the 1997 legislature refused to enact daytime speed limits. But highway fatalities eventually grew by 33 percent from the previous year, and even though they declined last year, the death toll was substantially higher than when numerical limits applied at all hours. There was little public dissent when legislators passed the new limits last winter.