Running itself is a fairly simple exercise, but running outdoors comes with its own set of unspoken rules. Is spitting frowned upon? Is there a polite way to pass slowpokes? We asked ultramarathoner, triathlete, and recent Boston Marathon qualifier Caitlin Constantine of the blog Fit and Feminist to share her own tips for running outdoors.

Should I wave at other runners?

“This is a tough one,” Constantine says. “I’ll put my hand up or give a nod, just because that tends to be my personality. I’ve got that whole Midwestern upbringing thing, where I don’t have a problem talking to strangers. But in other areas of the country, people might not be so open to that.” 

In the end, it’s up to you. Some people like to feel a sense of camaraderie with other runners, whereas others prefer to tune out the world around them. If you’re in a friendly mood, go ahead and give a short wave or nod.

What if I need to pass someone?

“If you’re coming up on somebody,” Constantine advises, “try to observe where they are and see how they’re moving—if they’re going to one side or the other—so you don’t run into them.” Don’t be shy about speaking up, either. Constantine will often “try to give a little bit of a signal, like, ‘Hey, coming up behind you.’” 

This is especially important on narrow trails and sidewalks, where your sudden proximity can catch people by surprise and it’s not always apparent whether you’re friend or foe. Be aware that women especially might be a little apprehensive and don’t like being snuck up on. “I would just urge men to be cognizant of that kind of thing,” Constantine says.

How much should I worry about cars?

According to the National Highway Traffic Safety Administration, cars killed more than 4,700 pedestrians—including runners—in 2013. This is no reason to call off your morning run, but it is a good reason to be careful on the streets. 

Always run against the flow of traffic, and always be alert. “I operate with the assumption that no car is ever going to see me,” Constantine says. “If that means that I have to slow down or stop or wait, I will. It’s not going to derail your training if you stop and wait for a car to turn in front of you.”

Finally, is it okay to spit?

“I’m a big spitter,” Constantine admits. “I recognize that it’s disgusting, and that a lot of people don’t want to see it, but I also need to do it for my own purposes—for my own performance and comfort. So I’ll always make an effort to aim it away from people so they don’t have to see it.” 

Running to one side, where you won’t risk accidentally hitting someone, is the best bet any time you need to expel some fluids. If you’re surrounded by other runners, as you likely will be in a race, Constantine suggests staying put and spitting toward the front. Just try to put some power behind it, for your own sake.