We don’t mean to toot our own horn (get it? road trip? horn?) but we’ve pretty much become experts on driving in Mexico. That’s what happens when you spend 18 months driving 24,737 miles thoroughly exploring 29 of the country’s 31 states (Monterey and Tamulipas, we’ll get you on the way back up).

Here are our top need-to-know tips about driving in Mexico that will help pave the way (again, get it?) for your own Mexican Road Trip Adventure. We sure wish we’d known this stuff before we left…

1. Fuel is cheaper in Mexico than it is in the US

During our travels we paid an average of $2.40 per gallon for diesel for our truck when fuel was cheaper and the exchange rate was stronger than it is now. Still, fuel costs remain below the US average. As of June 24, 2011 (calculated at the current exchange rate 11.81 pesos = US$1):

Magna (regular unleaded) was 9.24 pesos/liter  =  US$2.96/gallon;

Premium was 10.34 pesos/liter  =  US$3.31/gallon;

Diesel was 9.60 pesos/liter  =  US$3.08/gallon.  NOTE: there is virtually no ultra low sulfur diesel available in Mexico, but PEMEX has announced future plans to refine ULSD in the future.

Here’s a good place to find current fuel prices in Mexico.

2. There is only one gas station chain in Mexico

It’s called Pemex and it’s owned by the Mexican government which sets fuel prices for the entire country (though fuel can be a touch pricier near the US border and a touch cheaper in the free-trade zones in the southern border areas with Belize and Guatemala). This means you don’t have to waste time (and fuel) driving all over creation comparing prices at the Shell and the Exxon and the BP. What you see is what you get so just pull in and fill up.

3. All gas stations are full service in Mexico

Learn to say “Por favor, lavar el parabrisas” and they’ll clean your windshield too. We generally give the guy (and, occasionally, the girl) a couple of pesos for the effort. Another good gas station phrase to know: “Acceptan tarjetas de crédito?” (Do you accept credit cards?). Even if they say yes, ask them to run a charge through for the amount of gas you want before you pump. We’ve been left paying for a big fill-up in cash after the local Bancomer refused to process our credit card which the attendant said the station accepted.

4. You can use a GPS in Mexico–sort of

Magellan makes a GPS device that includes data for Mexican roads. It’s called the Roadmate 1470 and we used it throughout the country. Even so, it’s a bit tricky to use in small towns or in remote areas where data is thin and it can be confusing finding specific streets because name abbreviations are so often used. Sometimes it can be even more confusing in cities that can have dozens of variations of the same street name. Still, our Magellan did help us get oriented in big cities which is very helpful.

5. Better yet, buy a Guia Roji

Available at most big book stores in Mexico and at some big gas stations, this is the Rand McNally atlas for Mexico and still the best source of roadway and city maps plus it has a relatively accurate chart that will help you calculate what the tolls will cost if you choose to take the country’s pay highways instead of the network of free roads (see below).

6. Pay  Highway vs. Free Roads…

Pay highway pros: wide and well paved; usually bypass towns and villages; virtually unenforced speed limit; fastest way between two points–often 2-3 times faster than the free road route; you’ll often have the whole road to yourself; drivers on pay highways are automatically covered by limited insurance that covers civil liability, medical payments and funeral expenses (this does NOT satisfy your requirement to have Mexican insurance, however–see below); pay highways are patrolled by the Green Angels, an amazing fleet of bright green tow trucks driven by mechanics ready to fix what’s broken free of charge (see below).

Pay highway cons: tolls can add up (the 178 mile pay road between Puebla and Veracruz costs US$28, that’s more than a peso per kilometer, and you could spend more than US$350 in tolls driving from one end of the country to the other); since pay highways bypass towns and villages you don’t see much of real Mexico–driving on a pay highway is virtually the same as driving on a US interstate.

Free road pros: no tolls; since they pass through towns and villages you see Mexican life as you travel.

Free road cons: can be 2-3 times slower than the pay highway route; often narrow roads that connect towns and cities becoming slow moving main streets through each town and city along the way before turning back into a “highway” out of town; lots of topes (see below); cheaper trucking companies use the free roads too, so there are often big trucks on small roads.

You can get a detailed driving route with pay highway times and tolls from Mexico’s Secretary of Communications and Transportation. This is a particularly great tool for planning routes between cities.

7. The Green Angels make AAA look like a racket

Any driver on any road in Mexico can call the Green Angels and a bright green truck driven by bilingual mechanics will show up (8 am to 6 pm) ready to fix what’s broken for the price of the parts/fuel/oil (tips are appreciated). Green Angels patrol the pay highways, but if you don’t see one when you need one you just dial 078 and they’ll come to you.

8. Topes are a bitch

Tope (pronounced toe-pay) is the Spanish word for bump and is used for speed bumps. These concrete and rock humps in the road vary in steepness, width and severity but they’re all hellish. In the course of our Trans-Americas Journey we must have driven over tens of thousands of them. They are efficient and brutal–especially the ones that are unsigned and sneak up on you before you can slow down. There’s a reason there’s almost always a tire repair shack at or near a tope.

They’re also dreadful for your fuel economy and your shocks–which is part of the reason we upgraded to Bilstein shocks.

By the time we left Mexico we’d come up with two new terms relating to topes (no, they’re not swear words):

-nope (pronounced no-pay): What you find when you slow down and reach what you thought was a tope only to discover that it’s not.

-rope (pronounced row-pay): A tope made by laying a massive rope across the road. These can be even more brutal than the stone and concrete varieties.

9. Hoy no circula!

Mexico City’s air quality has improved dramatically in recent years, thanks in part to the innovative hoy no circula (today you can’t drive) rules that designate “no driving” days for all private vehicles in Mexico City and the state of Mexico based on the last number in your license plate. These rules absolutely apply to foreign drivers and it’s important to understand the rules, follow them and be armed with a good working knowledge of the program so you can make your case when a Mexico City cop pulls you over and (wrongly) accuses you of driving on a day or at a time you aren’t supposed to, which has happened to us. Here’s where to get complete hoy no circula rules in English.

You can also apply for a 14 day tourist waiver that exempts you from the hoy no circula rules in Mexico City.

10. Shakedown breakdown

Even armed with full knowledge of Mexican road rules and full compliance with said rules you will probably get pulled over by a cop in Mexico. Despite the fact that the Mexican government has made it illegal for the police to extort drivers for money (that had to be officially spelled out?), it still happens to locals and to foreigners. Soon after arriving in Mexico an expat tipped us off to this trick for getting out of these situations and after being pulled over multiple times in Mexico we can tell you that it works.

A. Act dumb and pretend that you don’t understand much Spanish, why you were stopped or what the cop is asking for. Maybe the cop will get bored and irritated and give up at this point. If he doesn’t…

B. Have the person in the passenger seat (also acting clueless and stupidly kind of excited by this “brush with the natives”) pull out a point and shoot camera and start happily taking pictures of this vacation memory in the making. Smile. Shoot some more.

C. Drive away. Because all cops know that extortion is illegal none of them will want to be photographed in the act. The cop will probably get angry when he sees the camera, but he will also tell you to get the hell out of there and the whole altercation will be over with no money paid, no shouting and no confrontation.

11. Mexicans are not bad drivers (they just have some wacky habits)

Two of the most important Mexican driving habits to understand are as follows:

A. Making two lanes into three lanes. Many two-lane Mexican roads have ample shoulders. This allows for an intricate ballet that involves slower traffic driving primarily on the shoulder allowing faster traffic to pass straddling the center line in an imaginary third lane. Cooperation from all parties is obviously required.

B. A left turn signal does not mean I’m turning left. Usually, it means “it’s clear to pass me.” This leads to some confusion when you really want to make a left hand turn which is accomplished by pulling over to the right of the road and waiting for all traffic behind you to pass, then turning left.

12. Not all Mexican auto insurance is created equal

You must carry Mexican auto liability insurance if you’re going to drive your own car in the country, but who you choose can make a huge difference. A company called Adventure Mexican Insurance Services acts as a brokerage for Mexican auto insurance and it is totally Trans-Americas Journey approved. They’re based in the U.S. and their 800# is always staffed with English speakers who can help with questions or issues, they offer great rates and they have fixers who can help solve claims problems. If we’d gone through Adventure Mexican Insurance Services instead of buying direct from stinky old GNP Insurance in the first place, we wouldn’t have gotten so screwed when a taxi ran into us and GNP jerked us around when we made a claim. That’s why when it was time to get a new policy we went right to these guys.

Use this link to purchase your insurance through Adventure Mexican Insurance Services and you won’t pay any more but we’ll get a small comission which will help us put a few more gallons in our gas tank.

13. You can’t beat a Mexican car wash

They’re cheap (less than 60 pesos, about US$5, for the exterior of our huge truck) and they’re often meticulous. Basically, a team of guys descends on your vehicle with high pressure washers and buckets of suds. No surface is left un-scrubbed, including the wheel wells and undercarriage. The whole thing culminates in a wipe down and polish of all rubber/plastic surfaces including your tires. We’ve had epic washes all over Mexico but the car washes in Mexico City and outside Playa del Carmen stand out. Set aside at least 45 minutes.

They’ll give the same treatment to your interior too for just a few pesos more.