To begin with, we strongly suggest you do not drive after you have had a few drinks. DUIs are seriously policed in Mexico and the Vallarta area just like they are in most countries like the US and Canada. Nevertheless, here is a description of how things work in Vallarta and possible ways to handle it if you should you ever be in this situation:

These Are The Applicable Laws

The first thing you need to know about these weekly sobriety check points is that they are not being done according to law and therefore illegal.  Let´s see why:

1. Article 20 of the Law of Mobility dictates that these programs should be carried out by the Secretary of Mobility, the Mexican equivalent to the DMV (CA) or the DPS (TX)   in cooperation with the municipal traffic police and that  the Secretary´s personnel must perform the actual test using the proper equipment.  In Puerto Vallarta the local traffic police do everything and the personnel from the Secretary of Mobility are not even invited to participate.
2. Article 186 of the same law considers three situations as possible outcome of such test:
   1. Fraction I says that if, according to the test, your alcohol intake is between .25 and .40 of milligrams of alcohol per liter of exhaled air (average equivalent to  2 to 3 beers within the last hour), then you should only be subject to a fine of approximately $10,000 pesos, roughly $800USD which you will have 10 business days, 2 weeks, to pay. If you have a companion who has drunk less than you have then they will advise you to let him or her drive and your car should not get towed.
   2. Fraction II dictates that if your alcohol level is between .41 and .65 milligrams of alcohol per liter of exhaled air (average equivalent to 3 to 6 beers within the last hour) then you are incommutably subject to between 12 to 24 hours of arrest in lieu of a fine. Your car will be towed as a precautionary measure and not as a payment warranty.
   3. Fraction III indicates that if your alcohol level is greater .65 milligrams of alcohol per liter of exhaled air (wasted) then you are incommutably subject to an arrest of between 24 and 36 hours in lieu of a fine.  Again, your car will be towed as a precautionary measure and not as a payment warranty.
   4. Furthermore, article 173 of the Reglamento (rules) of the same Law of Mobility dictates that in the cases when your vehicle must be towed, an inventory of existing damages should be taken in the presence of the driver and your car sealed off properly.  The Vallarta police do not have any way to seal the vehicle as stated by law.

These Are Possible Ways To Handle The Problem

What to do depends on how you feel about the issue and what fraction of the said article you violate. Let’s look at a couple of hypothetical scenarios:

Scenario One: If You Are Visiting or Simply do not Want to Hassle:

1. If your alcohol reading puts you in violation of Fraction I, you may want to pay something so they let you go home, no more than 500 pesos recommended and tell the judge who is present at the check point that you will pay the balance the following day or so. If they try to take documents like drivers license, license plates, etc away from you tell them that article 173 of the same Law of Mobility forbids them from doing so. If you decide not pay the balance, they do not have a legal recourse to come after you for payment.
2. If your violation falls within Fractions II and III then you must make some decisions. They will tell you that you are subject to a fine and arrest. The law reads that you must be arrested for maximum of 36 hours. No fine should be imposed as jail time shall be mandatory. Relax!, most likely they will not take you to jail since, as per Mexican legal protocol, they must put you in a special detention space away from the regular inmates.  The city does not have this special jail space. So, if you have enough money to pay the fine, do so but make sure you get the allowed 50% discount so it´ll be approximately   $5,000 pesos or $400USD.  Although illegally, your vehicle will be towed as a precautionary measure but you can get it the following day after you obtain a certificate of liberation.  The impounding of your vehicle should run you about $50USD for the towing plus about $5USD for every day of storage. Consider getting some legal assistance here as the balance of the fine and the towing charges can be contended as they were carried out illegally.

Scenario II: If You Live Here or Simply Would Like To Stand Up For Your Rights:

1. Should your alcohol intake fall within Fraction I, then do as in section (a) in the above scenario.
2. If you fall within Fractions II and III but before you take the breath test, ask whoever is in charge of the operation to prove to you that the person performing the test is a certified technician from the Secretary of Mobility.  Once you take the test they will have you talk to the judge at the checkpoint and most likely he will lie by telling you that you are subject to a fine, arrest, and the impounding of your vehicle.  Ask him to translate and read to you article 186 of the Law of Mobility; ask him to point to you where it says that.  The law only allows for a fine for violation of Fraction l. Fractions II and III call for mandatory jail time in a special area of up to a maximum of 36 hours even though such an area does not exist in Vallarta.  Your vehicle should be towed away as a safety measure and not as a guarantee of payment. Another easy option when violating Fractions II and III of the Law of Mobility is to pay something down so you can go home and seek assistance of and attorney.