Drinking and driving laws vary greatly from state to state, but the legislation is increasingly tough on offenders. Even if you aren't actually drinking and driving, you can end up running afoul of the DUI laws in other ways. These are some important facts you need to know before you get on the road.

You can get into trouble for allowing your passengers to drink while you drive.

If you're the designated driver on party night, you need to make sure that you know the laws in your state about open container laws when it comes to moving vehicles. Over Forty states and the District of Columbia prohibit any open containers of alcohol in a vehicle at all, while Arkansas and West Virginia only prohibit the actual consumption of alcohol while in the vehicle. 

In order to stay out of trouble, the safest thing to do is ask your passengers to keep any alcohol containers sealed until you get where you're going. Similarly, if a passenger wants to "get one more for the road," ask him or her to finish the drink before you get started. If you want to bring part of an already open bottle home from the restaurant or bar, make sure that it's legal to transport a pre-opened bottle in your car under those circumstances—many states do have an exception that will allow you to transport the bottle in your trunk, since it's clearly out of reach. However, don't make the mistake of thinking that the glove compartment is okay—it isn't.

Penalties for open container violations can vary from minor infractions (similar to a traffic ticket and usually punishable by a fine) to misdemeanors (punishable by a fine and up to a year in jail) depending on your state and the specific circumstances of your situation.

You can be charged with a DUI for allowing someone else to drive drunk.

You don't ever want to take the chance of getting into a car with a driver who is drunk—not only is it not worth the risk to your life, but it's potentially a felony. For example, in Tennessee, you can be charged with "DUI by consent" if you allow someone else to drive your car when you know that he or she has been drinking. 

You can also be charged even if you're the sober passenger of someone who is intoxicated. In at least one case, the court has held that someone who gets in the car with a driver who is too intoxicated to drive is "as guilty as the man at the wheel."

That means that if you want to call a cab because you don't feel sober enough to drive, don't take your buddy up on the offer to drive in your place, because you can both end up facing DUI charges.

If you do make a mistake and get into trouble, contact a felony defense attorney right away in order to discuss your case.