"There were no accidents," said Tim Rose, deputy director of Region 2 of the Utah Department of Transportation.
"I saw some people in the wrong lanes trying to make the wrong movements," he added. He was among a small army of UDOT officials watching the road Wednesday to see what tweaks may be needed.
"It is a matter of people paying a little more attention and getting used to the system," Rose said. "For the first day, I think it's working really well."
The Salt Lake Tribune witnessed several near-hits and other violations.
At 2200 West, several cars tried to turn left from a through-lane for opposing traffic, forcing oncoming vehicles to brake or swerve.
Also, as eastbound lanes were being reduced from four lanes to three at the end of rush hour, an eastbound driver properly tried to turn left out of what moments before had been a through-lane for traffic in his direction. A motorist behind him apparently didn't notice the transition. The second vehicle came up on him quickly, honked and swerved. The would-be turner panicked and proceeded forward.
"People need to get used to [the fact that] their left-turn lane in the morning is not the same left-turn lane in the afternoon," Rose said.
Jason Jo, manager of a 7-Eleven at 3200 West, said he noticed during recent days as lane-control lights have been on without changing directions "that people seem confused where the lanes begin. I saw one car almost stop because it was trying to figure if it was in the right lane, and others almost hit it. … Some also don't seem to notice intersection lights" amid row after row of lane-control lights.
During the morning rush hour, 5400 South has four eastbound lanes, a center turn lane and two westbound lanes. In the evening, that reverses with four westbound lanes, two eastbound and one center turning lane.
The stretch has overhead electronic lane-control signs every 500 feet with green arrows in lanes where traffic is allowed, red X's where it is not, yellow X's where traffic should begin moving out of lanes because directions are about to change, and yellow left-turn markers for the center turn lane.
Rose said he noticed Wednesday that many cars initially were hesitant to use lanes nearest the center, and instead crowded the far-right lanes. "But as traffic filled in, people got it and were more and more apt to use that far left lane," Rose said. "There were virtually no delays today. The traffic flowed very smoothly."
Rose said UDOT will watch the lanes closely in coming days to adjust timing of transitions and "We may make some changes at the intersections to try to make it clearer so people get in the right lanes."
His main advice: "It's very clear, if you look up, where you should be at. If you have a red X above your head, you need to get out of that lane. If you have a green arrow, do not stop and try to make a left turn."
The new flex lanes could not be blamed for all problems Wednesday. For example, a truck stopped in a proper left-turn lane. Then it simply decided to run a red light and turn.
"We see a lot of people not obeying traffic signals all the time all over the system, not just here," Rose said. "There are some people who are going to violate no matter what."
See how it works
To view an animation of how the new flex lanes work, go to udot.utah.gov/flexlanes..