As anyone who’s sat for their driver’s license exam hopefully knows, a driver is permitted to make a right turn at a red light after coming to a complete stop, provided they first yield to pedestrians or other vehicles in their path. That is, of course, unless there is a “No Right On Red” sign posted. And for Watertown resident Maryann Merigan's taste, there are too many “No Right On Red” signs in these parts.

"I can’t help but think it’s almost as if I can’t be trusted to know when to turn on red," said Merigan.

Merigan reached out to us here at the Curiosity Desk in the hopes we could help her understand more about who decides when to restrict a right turn on red, and how that decision is made.

"I am curiouser and curiouser about who sets the rules for no turn on red at our intersections," Merigan wrote in an email. "Is it done by town? Is it done by the state? I'm pretty sure most of us know how to stop and then turn on red. I would love to know who is in charge of making those decisions.”

We dug into answers for Merigan, and along the way also learned how the 1970s oil crisis led the federal government to push all states to allow right on red, which New England state was most reluctant to go along with it and why the practice — once embraced by environmentalists — has increasingly fallen out of favor.

WATCH: Who Decides If You Can or Can't Turn Right On Red While Driving?

If there is something you've been itching to know more about, email The Curiosity Desk or send in your question below. Edgar might just dig up the answer in a future episode. For more from The Curiosity Desk, follow Edgar B. Herwick III on Twitter and subscribe to the GBH News YouTube Channel.