For more than a week each August, the Sturgis Motorcycle Rally brings big-city traffic challenges -- and then some -- to the usually peaceful northern Black Hills community.
But lots of cooperation between state and local government officials -- and lots of stop lights - help keep the bikers moving.
Each day, Sturgis hosts tens of thousands of bikers, not to mention all manner of other vehicles. So rules are important. So are street lights and stop signs and a variety of instructions on where to park and walk and drive and wait.
A temporary traffic-control system set up each year is essential to keeping the rally running, in and out of town, says state Department of Transportation traffic engineer Monica Heller.
A key travel route is Highway 34 from Sturgis east to the sprawling Buffalo Chip Campground.
"We put up five traffic signals on 34 from Nellie Street in Sturgis all the way out to The (Buffalo) Chip," Heller says. "We've got five signals that are only in operation during the week around the rally."
And it isn't just the state that manipulates traffic flows. Moving all those cars and trucks and vans and pickups, and especially all those motorcycles, creates a monster of a traffic issue that multiple agencies must address.
Transportation officials constantly monitor temporary lights, some of which can be remotely controlled. Two key traffic points are at the interstate ramps.
"Those are the really primary ones we're concerned about, exits 30 and 32, because we don't want traffic backing up onto the interstate because of the high speeds there," Heller says. "So those are the ones we keep the closest eye on."
Temporary lights also help assure easy access to the Veterans Administration health-care center just east of Sturgis and manage the meeting and mixing of heavy traffic at the entrance to the Buffalo Chip and the intersection where Highway 79 heads north off of Highway 34.
In the heart of Sturgis, city officials rely on lights, all-way stops and common sense by drivers and walkers. So far, it all seems to be working -- at least in Sturgis and the immediate area.
"Last I heard, injury accidents are down, fatalities are down, so that's always a good thing," Heller says. "That's our primary concern is safety."
Even as they manage the heavy traffic flow in and around Sturgis this year, officials are looking ahead to bigger headaches in 2015. The 75th Sturgis rally could be a record-setter and is certain to create added traffic-control challenges.
"We're just trying to tweak some things and look to see what we can improve for next year," Heller says. "Because we expect a bigger crowd next year, with it being the 75th."