Runners make their way through the congested main street of Summerhaven towards the finish of the Half Marathon portion of Mount Lemmon Marathon.

Ron Medvescek/Arizona Daily Star

If you were planning to visit Mount Lemmon on Sunday morning, it might take a little bit longer to get up and down the mountain.

While all businesses, restaurants, trail heads and campgrounds will be open, the downward lane of Mt. Lemmon Highway will be closed for runners participating in the Mount Lemmon Marathon.

Cars will still be able to get up and down the mountain on the upward lane, but drivers must wait for escorted convoys before they're allowed to travel up or down the mountain, said Jared Rohatinsky, a spokesman for the marathon.

The restriction will begin at 4 a.m. and the marathon is expected to last until about 2:30 p.m.