"It's very necessary for the safety of all canyon users," Iltis said. "It's a relatively narrow road and the potential for conflicts is high if users aren't acting in a predictable manner."
The danger often comes when cyclists zipping downhill round curves only to find the roadway clogged from shoulder to shoulder with pedestrians and dogs.
New signs direct all uphill traffic bicycles and pedestrians to the "creek side" of the road. On the way down the canyon, the signs specify that pedestrians remain on the creek side of the canyon but directs cyclists to the "hill side" of the road.
The rules also say that cyclists should travel no faster than 15 mph. In addition, they mandate that dogs must be on a leash no longer than six feet in length.
Pedestrians can use the canyon every day. But bicycles are allowed only on odd-numbered calendar days. Cars can go up City Creek on even-numbered days.
Pedestrians should realize the canyon road is plied most every day by vehicles with the Salt Lake City Department of Public Utilities, said Art Raymond, a spokesman for Mayor Ralph Becker.
"Our goal," Raymond said, "is to get everyone to share the road in a safe manner."
Avenues resident and regular canyon user Mael Glon said the signs can't help but make the canyon safer. He likes to walk Lucy, his Siberian husky, in City Creek. He also bikes there regularly.
"I've had issues when I'm cycling, especially coming downhill around blind curves," he said. "And you have people who take their dogs off the leash."
On the other hand, a 24-year-old Avenues resident who didn't want to be identified said the new signs were "overkill."
"I'm not fond of big signs in natural settings," she said. "They have them about every 10 feet, and it seems like there isn't that much danger."
Resident Buddy Beck, who walks the canyon about three times a week, said some pedestrians don't pay attention. Maybe the signs, he added, will change that.
"People who aren't frequent walkers in the canyon don't realize that, on bike days, it can be dangerous," he said. "I saw a little girl almost get run down by a cyclist.
"He wasn't doing anything wrong, she just wasn't paying attention."
The keys, said Laura Briefer, the city's water resource manager, are common sense and common courtesy.
"While enjoying the canyon, we must all remember to be considerate of others and follow the rules of travel."