The summer we survived proves it once and for all: There are only two seasons here in Central Texas — Summer and Not Summer. (Thank you, global warming.)

And with temperatures dipping back down into the brisk not-100s, people who haven’t exercised outside in months, fearful of the dual threats of organ-baking temperatures and smoke-infused air, are now finding the courage to leave the gym. As a result, we have another health threat to worry about during our respite from the risk of heat stroke: clueless, collision-causing amblers, joggers and Sunday cyclists drifting aimlessly around our trails.

That means it’s time for a refresher course on trail safety and etiquette. If you only remember one safety rule from this column, make it this: CRASH! That’s an acronym that stands for Car Rules Apply (the) Same Here. In other words, basic rules of the road apply on the trail, too. Failing to respect the CRASH! rule could result in your being involved in one. So in an effort to spare you from having to pay a pound of flesh, I’ll take the liberty of fleshing out the rules a little more:

Get over yourself. In the U.S., cars drive on the right side of the road, slower traffic stays in the far right lane, and faster traffic passes on the left. The same thing goes when you’re on the trail. There should always been at least enough room for two way traffic, plus enough space to pass in the middle.

Wide Loads. I recognize that the trail is for everybody, not just athletes. But just as an athlete’s use of the trail does not take precedent over the social walker’s use of the trail, the opposite is also true. Your family reunion’s post-Sunday brunch stroll to feed the ducks should not turn into a reenactment of Hands Across America that creates a human road block.

If you’re on a wide stretch of trail and it’s not rush hour, it might be possible for you, your mom, your grandmother and your plus-sized aunt to drift along side by side at a glacial pace without creating a safety hazard. But on narrow stretches, manners and safety dictate that you drop down to a single file. And you with the quadruple stroller: It’s awesome that you’re getting back out here so soon after you gave birth to four babies at one time. But you’re going to need to hug the right side of the trail as tightly as possible with that tricked-out, land barge of a stroller.

What Would Cesar Do? The most important thing Cesar Millan has taught us is that a show featuring Zen dog tips communicated by a guy who speaks with a hot accent and wears Banana Republic’s latest fashions makes for great TV. The second most important thing Cesar Millan has taught us is that humans need to be in charge of their dogs, not the other way around.

Keep your dog on a short leash — literally. Don’t give him enough rope for him to dart around erratically, running up to this dog or that person, and hog-tying a half a dozen people in the process. And if your dog isn’t trained yet, leave him at home. The trail is no place for an untrained dog.

Student Drivers. And speaking of things that are not yet trained, can we talk for a minute about little junior on his tike bike? I can tell he’s the apple of your eye by the way you’re beaming at him as he dangerously zigzags his way back and forth from one side of the trail to the other. But your parental pride is blinding you from the fact that the situation he is in is not safe.

You would never let him drift in and out of traffic on Memorial on his training wheels. It would be dangerous for everyone, especially him. The situation on the trail is similar. Many of the runners and cyclists are moving along at a pretty fast clip. And unlike you, little junior and how adorable he is are the farthest things from their minds. While they’re working out, they’re abiding by the rules of the road and they reasonably assume that everyone else is, too.

If little junior darts into oncoming traffic, there’s a good chance they won’t see him until it’s too late. The trail is for cyclists who already know how to ride a bike without training wheels. Until little junior gets the hang of it, keep him on non-busy streets and cul-de-sacs.

10-4, Good Buddy. When you’re cruising down the street and you see one of your friends driving by in the opposite direction, do you: (a) Slam on your breaks, come to a complete stop right where you are, roll down your window and chew the fat until you’re all caught up on every detail of each other’s lives; or (b) Honk lightly on the horn, and if you’re the super-animated type, roll down your window and wave?

If you answered (a) you should stay off the road and the trail. One of the nice things about the trail is that when you see a friend, it is perfectly acceptable to say "hi" without stopping. But it’s both a breach of etiquette and a safety risk to stop in the middle of the trail even for a brief conversation. Doing so can create an inconvenience at best and a hazardous situation at worst. If you want to catch up, send them a Facebook message or a text when you’re done with your run.

Roadside Maintenance. Everyone has a little trouble on the road once in a while. But often times, the real danger isn’t presented by the maintenance issue itself, but rather the dumb decisions people make when they are trying to fix the problem. For example, plenty of people survive blowouts only to get plowed into when they’re changing their tire. Why? Because they didn’t choose a safe spot to stop or they failed to pull over far enough.

The trail is no different. Need to tie your shoe lace or send a quick text message? Make sure to pick a wide, flat stretch of the trail, then pull over — way over.

Emission Standards. If you’re doing it right, exercising will lead to two things: Sweating and heavy breathing. Fresh sweat smell is to be expected. But old sweat that is chemically reactivated by new sweat creates a smell that is foul enough to make even the toughest athlete weep.

No one deserves to unsuspectingly suck in a couple of lungfuls of that. So do everyone a favor and wear clean clothes and deodorant. And while we’re on the topic of air quality, when you’re walking around the trail, it’s not the right time to light up a cigar — even if it is a really expensive one. I know you read in Esquire Magazine one time that smoking cigars makes you look cool, but knowing the right time and place to smoke your cigar will make you look smart and considerate — and nothing is cooler than that.

Blowing and Going. If your dog gets car sick when you’re driving him to the vet, do you just leave the mess there and not bother to clean it up? Of course not. And if you need to blow your nose when you’re driving to work, do you not bother to get a tissue and just block one nostril and blow as hard as you can, letting it spray everywhere? No way. You wouldn’t do those things in your car or your house or even your bathroom. So, don’t do them on the trail, either.

So, during the next several months of Not Summer, head down to the trail and enjoy yourself — but be responsible about it. In addition to sun block and your BP-free reusable water bottle, bring your good sense and manners along, too. That way it can be happy trails for everyone.