Sunday car sales aren't just proscribed by state legislation, they're criminalized. It's a Class B misdemeanor to buy or sell a car on Sunday:
State Sen. Phil Boots, R-Crawfordsville, is pushing legislation to eliminate the regulation, which he considers antiquated. Boots is also sponsoring a bill that would lift the ban on Sunday alcohol sales.
"It seems to me it's another government incursion into private industry's decision to be open or not open on Sunday," Boots said. "It's also an inconvenience for certain people that want to shop on Sunday."
He's exactly right. I'm one of those people who have enjoyed one aspect of the lack of Sunday sales -- being able to walk around and compare cars without getting pressure from salesmen. But that shouldn't be a matter of law that prevents us from buying on a Sunday if we want to.