When a Redditor asked, “People with ‘street smarts’—what is your most street tip?” the internet answered with a wealth of safety information. One of the simplest pieces of advice was to walk “against” traffic so a car can’t follow you without you knowing.

The idea is simple. If you’re on a road with sidewalks on both sides and choose to walk on the right sidewalk, you’re walking “with” traffic. That means a car could conceivably cruise along behind you without you noticing for a while.

Here’s the full tip: “Always walk on the side of oncoming traffic so cars can’t follow you. If you feel followed, cross the street and run in the opposite direction.”

For a car to truly follow you walking, you’d need to not spot its headlights. In addition, traffic would need to be nonexistent or moving so slowly that the car could cruise along at walking speed. This isn’t a very likely scenario. But choosing to walk or run “against” traffic means it’s less likely for drivers to yell or even catcall you. It also allows you to see oncoming traffic, so if someone is driving unsafely and might hit you, you have a bit of time to react. Still worried about a car following you? There’s a simple way to test whether your headphone volume leaves you vulnerable.

The path you take along the sidewalk also matters. Another commenter, a retired security guard, urged Redditors to “walk on the outside of the sidewalk away from the building; this helps prevent someone from grabbing you from an alley or doorway.”