We’ve all been there: You’re on a road trip, driving through a city, and one of your passengers pipes up, “I need to go to the bathroom!” And thus begins the anxiety-inducing hunt for a public restroom.

Gas station? Too sketchy! Rest stop? Too far away! So what’s a driver to do? According to a retired detective, the ultimate public restroom life hack is to go to a swanky hotel. He shared details on this tip in the most surprising place.

A user on the Quora platform for questioning experts and professionals asked the following: “People in law enforcement, are there any tips/unknown loopholes people (criminals and citizens) don’t know about?” They likely expected advice on traffic stops or being questioned by police. But the most popular answer was a whole slew of pro tips from Detective Benjamin Bender (retired) of the St. Louis Metropolitan Police and Air Force military police. Here’s what he said about hotel bathrooms:

“If you’re out and about in a larger town and all the sudden have to take a crap it can be difficult to find a clean bathroom. Your best bet is always to go to a really big Hotel like a Hilton, Adams Mark, etc… The nicer chains have huge lobbies with massive bathrooms done in Marble. Spotless. Some so big you could play half court basketball in there. Even better they’re almost always empty. So if you’re on the road and some high end hotels are nearby that is your best bet.”

– Benjamin Bender via Quora

First and foremost, yes, most hotels have lobby restrooms. And yes, they are often empty because all the guests also have rented a room which includes a full bathroom. So why do they have a lobby restroom? It may be to serve patrons of restaurants, bars, or coffee shops in the lobby. Or it may just be part of the “hospitality” mindset. Better yet, hotels have a cleaning staff come through daily. So these lobby restrooms are almost always clean and well-kept.

Making a hotel restroom rest stop work

So can a non-guest walk into a hotel lobby? Yes, almost any hotel will let you just walk in. They often have guests coming just for the restaurant or bar. If you want to put your feet up during a road trip, buying a coffee and relaxing in a hotel lobby is a great option.

A nice hotel in the suburbs may have a large parking lot with no gates. So you can just park your car, and you and your passengers can walk to the lobby. At night, hotel security may make sure that all the cars in the lot belong to guests. But during the day, they are less likely to bother you. If you are concerned, just ask the concierge at the front desk if your car is alright in their lot for a few minutes.

If you are in a city’s downtown area, parking may be more difficult. Those hotels may have an attached parking garage, a concierge parking service, or both. In this case, just politely ask a valet attendant what your parking options are. If it’s an emergency, your passengers may be able to go in and use the restroom while you wait with the car out front. Or you may be allowed to park in the garage for free if you all go to the hotel for a meal.