Road Atlas planning with car keys
For when your smartphone gets lost too...

Road Trip Tips — Understanding the Interstate System and Navigation 101

Planning for a road trip? Mapping out your route is one of the most important steps, especially for those who seem to have no internal compass whatsoever. Sometimes it’s great to go off the beaten path, but only if you know how to get back on at some point. Here are some tips for determining directions, figuring out maps, mile markers, and how to get where you are going without going too crazy.

As always, I highly recommend buying a paper atlas and keeping it with you as a backup to your smartphone or GPS device. The Rand McNally Road Atlas is one of the best on the market, but others are available. It’s just a good idea to keep one with you in case your phone or GPS battery dies, loses its signal, or takes you to a closed-off road (hello, Niagara Falls).

I know I keep bringing up the dangers of relying on your smartphone or GPS entirely, but I’ve driven around enough to know that signals and batteries die, and that dead-ends are sometimes ignored. (Seriously.) Also, if the weather starts picking up and you are under heavy cloud cover, sometimes the signal acts up. Just use Siri or Google as your main navigation device and keep your paper Atlas in the car as a backup.

Never Eat Sour Watermelons — Directions 101

A direction is a way to a place, and directions are most commonly provided regarding what we know as cardinal directions. The cardinal directions are North (N), East (E), South (S), and West (W). Ordinal directions refer to the directions found equally between each cardinal direction. These are northeast (NE), southeast (SE), southwest (SW), and northwest (NW).

When I was little, my father taught me the old mnemonic device for remembering the four directions.

  • Never = North
  • Eat = East
  • Sour = South
  • Watermelons = West

How is this relevant you ask? It’s important to get used to not only know the direction but to understand the order of the directions. If you know what direction you are facing, it’s a good trick for remembering how to find the other directions. If you are facing north, stick your right arm straight out to your side, and that’s east, behind you is South, and your left side is west. Sometimes the main trick is just figuring out what direction you are facing.

Understanding Directions on a Map

All maps are, by default, focused with the cardinal directions in their proper order. Here’s an example of Google Maps with directions from Dallas to Chicago. I have taken the liberty of writing in the directions, just to give an idea of what you are looking at.

  • North is at the top of the map (think Montana or cold; Canada)
  • East is on the right side of the map (think East Coast)
  • South is at the bottom of the map (think Texas or hot; Mexico)
  • West is to the left side of the map (think West Coast)
Map with the directions written in. Get your bearings before heading out. Map data ©2018 Google
Map with the directions written in. Get your bearings before heading out. Map data ©2018 Google

In this example, you want to take a road trip from Dallas to Chicago. Chicago is north of Dallas (northeast, technically). If you decided to take a detour to Nashville, you would be heading east. Let’s look at what Google Maps gives you. Your Atlas or Apple maps will give you a similar view. You can rotate your map in your smartphone, but there is almost always a way to re-center your view. Try to keep it with north at the top of your screen. It really does help you get your bearings as you start remembering what direction certain locations are from your destination.

Homework: Learn Your Interstates

I’m not suggesting that you memorize every street or country road on your map. However, knowing the biggies will be extremely helpful. When you are heading to a destination, review the route beforehand to figure out what the significant interstates or highways are. It may even be beneficial to take a sticky note and write them down to help you memorize them better.

Here are some of the basic rules about interstate travel.

  • Interstates are laid out left to right and south to north. The lowest numbered freeways are on the west coast and in the south and the highest numbered ones are on the east coast and the north. Mile markers also correspond to this pattern; they start with 1 on the western portion of the state and increase in numbers to the eastern portion. Mile markers begin with 1 in the southern part of the state and grow as you head north.
  • Even numbers (such as I-10) are east-west routes
  • Odd numbers (such as I-49) are north-south routes.
  • If you see an interstate with 3 digits (I-310), it is known as an auxiliary interstate and is a branch of the main highway. These generally occur around a big city.
    • One with an even starting digit (I-410) means that the auxiliary road meets an interstate at both ends, or as a loop. In general, most interstates that start with a 4XX are loops. For example, I-410 is a loop around San Antonio and intersects with both I-35 and I-10.
    • One with an odd starting digit (I-310) means that it has an interstate highway only at one end and may have a city road or highway at the other end. I-310 in Louisiana for example intersections with I-10 at its northeast end and Highway 90 at its southwest end.

For example, let’s take a trip from Tyler, Texas, (starting on I-20) to New Orleans, Louisiana.

  • Interstate 20 (I-20) is in the northern part of the state and goes West to East between Shreveport and Vicksburg. I-20 is an even-numbered route, so it is east-west.
  • Interstate 49 (I-49) is the main north-south road that will take you from Shreveport down to I-10. I-49 is an odd-numbered route, going north to south.
  • Interstate 10 (I-10) is another West to East that takes you across the southern part of the state from Lake Charles over to New Orleans. It is also an even-numbered route.
Directions from Tyler, TX to New Orleans, LA on major Interstate roads. Map data ©2018 Google
Directions from Tyler, TX to New Orleans, LA on major Interstate roads. Map data ©2018 Google

These three main roads will take you to the major portions of the state. Most of the other roads and streets in town will provide signs that eventually say something like I-20 junction, 3 miles.

There are quicker ways to get to your location, small highways and back roads, for example, such as I-49 S to US-190 E. However, if you are prone to get lost easily, stick to memorizing the main interstates.

It’s like when you first move to a big city, and the locals tell you to memorize certain roads. In Richardson, Texas, Belt Line Road is a major east-west road, and Coit Road is a major north-south road. Interstate 75 is the main freeway that goes through town. You can exit Belt Line Road on I-75 and be in downtown Richardson. It’s a similar mind game with learning your highways of where you are going. Just a little prep beforehand can save you lots of headaches and gas.

When driving, you may zone out and your GPS may lose its signal. However, if you know that you need to head from I-20 in Shreveport, then South on odd-numbered I-49 Lafayette, and then east on I-10 towards Baton Route, you’ve already won part of the battle. I know people who’ve stuck that sticky note to their car dashboard, to a paper map, or even to the interior windshield (be careful with that one) just so that they remember the basics. When you get into small roads and country roads, it can be a bit tricky. However, the good news is that these roads almost always lead back to a major highway or interstate. Just get your bearings and don’t panic.

Note: Sometimes rules are broken, but that is why you need to review your map ahead of time. For example, I-35 is a north-south road but outside of Emporia near Kansas City? It heads east for a time. However, it does start heading north again, eventually.

The Importance of Mile Markers

Mile Marker 219 heading West on I-64 in Virginia.
Mile Marker 219 heading West on I-64 in Virginia.

As you are driving along the Interstates, you will notice little signs every mile or so that state “MILE” followed by a number. It sometimes gives what Interstate you are on, but they usually just state what mile you are on with smaller highways. For example, this sign says that you are heading West on I-64 and are at Mile Marker 219 in Virginia. These markers are there to help you determine what directions you are going and how many miles it will take to get between destinations.

In general, mile markers increase moving West to East and South to North.

Here’s a sample map of Texas. I’ve followed I-10 across the state and I-35 from top to bottom. As you head east through Texas, the mile marker on I-10 will increase. As you head west, it will decrease. Not sure what direction you are heading? Start paying attention to mile markers and exit signs (they match). If the mile marker starts decreasing on an east-west route, you are heading West. If it starts increasing, you are heading east. Going from San Antonio to New Orleans this summer? Look for the increasing mile markers. At the Louisiana state line, it will start back at 1 and start increasing again.

Mile marker starts and finishing points for I-10 and I-35 in Texas. Map data ©2018 Google
Mile marker starts and finishing points for I-10 and I-35 in Texas. Map data ©2018 Google

What? Okay, for example, let’s say that you come from Oklahoma along I-35 into Texas. Right outside of Gainesville, you will see Mile Marker 504. What does this mean? It’s 504 miles from the Texas/Oklahoma border to the Texas/Mexico border near Laredo where I-35 ends. As you start driving south, it will start decreasing from 504, 503, 502, etc. If you are leaving Dallas towards Oklahoma City and you see mile marker 115 on I-35, you’re really, really lost. Turn around and head in the opposite direction. Also, stop and get gas.

Let’s take that exit, turn around, and get back on I-35 heading North into Oklahoma. You are heading North, but you are at the southern part of the state. Once you enter Oklahoma, what is the first exit you see? Exit 1, 77 North. It starts back over and will continue all the way to the Oklahoma/Kansas line. When you hit mile marker 235 going north, you know that you are near the Kansas state border. The mile marker will restart and start counting again at the border.

Exits Correspond with Mile Markers. If you see a big sign up ahead that says Gas, take exit 217, and you see that you are heading West on I-64 at Mile 219, your exit is about two miles ahead. It sounds confusing at first, but you will get the hang of it if you start paying attention to those mile markers and to the road.

Keeping Kids Entertained and Adults Deafened. I grew up with a truck driver father who always used to give my brother and me instructions on long road trips to keep us entertained. This was long before cars came equipped with movies and wi-fi. I learned quickly how to tell where we were going and why and didn’t drive them crazy with questions like “Are we there yet?” because I was the one letting them know. He used to make us keep track of mile markers so that we helpfully let them know when we were almost there by shouting out as we were within 2 miles of a town, like “ABILENE!” or “DALLAS!” Sorry, Mom.

I helped one of my friend’s children with his counting by teaching the same trick on frequent trips between Abilene and Dallas. He would count down the mile markers and shout “EASTLAND!” or whatever every time we got within two miles of a destination point. Sorry, Ana. He’s 16 now. Hopefully, he’s grown out of it. Or, at least only does it internally like I do.

Roadside Assistance — Final, but Important Note. It’s also important to know what mile marker (or exit) you are near in case of a roadside emergency. If you must call either the state number (#511?) or AAA for roadside assistance, they will ask you where you are. Most often, they merely mean what mile marker so that they can get to you quickly. Your GPS may work fine, but it’s usually best with roadside assistance to just state that you are near mile marker 500 on I-35 in Texas. Not sure? Start walking, and you will see one soon as they are put at mile increments.

Understanding Direction Based on the Sun

This isn’t as important as it used to be but here is another old trick. Look at the sky. Some people can determine directions naturally by watching the sun. The sun rises in the east and sets in the West. In the northern hemisphere, the sun is at its highest at 12 p.m./noon. So, if it is early or later in the day, you can look for the sun to orientate yourself. Before noon, the sun will be moving from the east, and after noon, it will be going towards the west. However, if it’s in the afternoon, it can get confusing to figure out exactly where it is without blinding yourself.

A compass in your car might be a better alternative. Your smartphone or car probably comes with one built in. I know I often sound like a technophobe, but I’m not. It’s embarrassing how many smart devices I have. However, I also know their limitations, especially in some very remote areas. If your car does not come with one built in, buy a small compass, just in case.

Road Trip Necessities

Here are a few items that I highly recommend keeping in your car for emergencies or small inconveniences.

Happy Traveling!