"Every season or holiday she will dress up, either as the Grinch or Mrs. Claus or a reindeer. She has been a turkey, she has been the Easter bunny," Ericka Madsen, a parent, told KSL.
Caldwell lives in the neighborhood where she works as a crossing guard, and her aim is to make the intersection safer for children heading for school.
"Nobody wants to hit the Grinch, so people do slow down," Caldwell told KSL.
In a more serious vein, parents have come to trust their children to Caldwell.
"I don't have to worry about crossing this dangerous street with Karen here, she makes sure that everyone gets where they need to be and with a smile and a lot of cheer with her costumes," parent Kristin Wynder told KSL.