Summertime is road trip time. There's something magically liberating about hitting the open highway for a summer getaway—especially when it's with someone you love. Following these 12 etiquette tips will help ensure you are still speaking to one another when you reach your destination:

1. Offer to take turns driving. Even if one of you normally does all the driving when you travel by car close to home, don't assume that person wants to drive all 12 hours of the trip. Offer to give them a break and ask again later if they say no the first time.

2. Refrain from offering critiques of the driver's performance. Backseat driving and slamming on imaginary brakes from the passenger seat are sure ways to create tension and unpleasantness in the vehicle. If you know you are going to be nervous with your spouse at the wheel, bring reading material and don't look up. If you're honestly afraid for your life, phrase it in such a way as to avoid a fight, "I'm a little worried that we're too close to this car. I can take a turn driving if you need a break."

3. Don't make your passenger cower in fear with your driving habits. If you are the driver, no playing "Indy 500" on the interstate. No tailgating, no texting, no road rage, no cursing the other drivers. All your risky maneuvering and lane-switching may possibly get you there 10 minutes faster, if that. It's not worth it.

4. Take turns playing DJ. If you can't find common musical ground, take turns choosing what you listen to. When it's your turn, try to pick something you both will enjoy, if possible. Otherwise, each of you take an hour where you make the choice. Also, never change the music without asking first—frequent mid-song station switching can be hazardous to the sanity of your passengers.

5. Be ready for whatever temperatures await you. On a long road trip, it's fair to defer to the primary driver on temperature controls. They need to stay comfortable and alert. That said, if your spouse likes the cab so cold that your lips turn blue on the average drive to the store, be ready on a longer trip by bringing supplies to help you manage your own temperature: blankets, sweaters, wool hats, whatever it takes. Similarly, if you expect the temperature to be warmer than you like, wear warm-weather clothes and bring plenty of cold beverages.

6. Keep your ear buds in your bag. You're in this together, so if you're the passenger avoid keeping your ear buds in the entire drive. Be available to chat, discuss directions or lunch options. Staying engaged helps the driver stay focused and not get drowsy.

7. Factor in rest stops. If you're the driver, accept the fact that your passenger will have to go to the bathroom at some point, even if it means all those 18-wheelers you passed will once again be in front of you. When your spouse alerts you to nature's call, pull over at the next opportunity. Don't try to see how long she can hold out.

8. Fuel up with snacks and meals. Nothing keeps the mood light on road trips like good snacks. Be sure to pack an ample supply. Also, when it's time to stop for a meal, try to find something you'll both enjoy or take turns choosing.

9. Get enough rest. Remember, safety is the top priority. If the driver is getting drowsy, it's time to give him or her a break or stop for the night. Never risk the safety of yourselves and those around you to try to get to your vacation spot a few hours earlier . If you don't get a good night's sleep, you'll just be exhausted when you get there, so rest along the way.

10. Take the right stuff. A brief list of some essentials: your phone, computer, e-reader, camera and chargers for all of them; blankets and pillows; a flashlight; an emergency kit with flares; toilet paper, tissues and paper towels; hand sanitizer; a spare key; sun block; plenty of drinks and snacks; and the number for the roadside assistance service you signed up for (you did sign up for roadside assistance, right?)

11. Have directional backup. Yes, your GPS is wonderful, but what happens if it accidentally collides with your iced coffee? Technology is great but have paper backup as well, whether it's a roadmap, atlas or directions you printed out.

12. Relax and enjoy the ride. You are on vacation, after all. Don't become a slave to the clock or the speedometer. Enjoy the time you are spending on the road with your spouse, family or friends and remember that the point is not to make good time, but to have a good time.

Diane Gottsman, a nationally recognized etiquette expert, is the owner of The Protocol School of Texas, a company specializing in etiquette training for corporations, universities and individuals, striving to polish their interpersonal skills. You can reach Diane at 877-490-1077 or www.dianegottsman.com. You can also follow her on Twitter @: www.twitter.com/DianeGottsman.