Drivers who were suspected of driving under the influence used to have the ability to refuse to submit to a breathalyzer test or a blood test for law enforcement agencies to determine the blood alcohol content at the time of an incident if the agency was unable to obtain a warrant. Since September 1, 2009, however, there are several situations where a warrant won't be needed before a patrol man or trooper can ask for a blood test at a medical facility.

The chief criteria relate to the health of the occupants. For example, if a passenger or the driver was injured at the time the police officer suspects suspicious behavior, that can be grounds for a mandatory blood test. A test can also be required if one of the passengers is 15 years old or less, even if the driver has recently attended a Texas defensive driving course online.

The second set of rules for eligibility for a blood test revolve around limiting the possibility of repeat offenders. If the officer on the scene can produce evidence that the driver has been convicted of driving while intoxicated two or more time, then he or she can ask for blood to be drawn. A single conviction with an occupant under the age of 15 is also grounds for the test. Finally, intoxicated-related offenses such as assault or manslaughter can provide a legal rationale for the process.

These are new changes to a law that had previously allowed law enforcement personnel to only ask for a blood test if they explained the situation to a judge who provided a warrant for the results of the examination. While police argued that the time it takes to obtain such a warrant can lead to inconclusive or inaccurate results, civil rights advocates have claimed that the new law may lead to wrongful arrests.

It may also be an issue for the healthcare professionals who are asked to draw blood. The potential for abuse by law enforcement officers opens the doctors and nurses performing the test to potential lawsuits if the arresting officer used faulty evidence or reasoning in order to obtain the test.

Those exceptions aside, the new law means that drivers must consider the possibility that they will not be able to refuse tests following a DWI stop in Texas. While drinking or consuming illegal substances and then driving are not recommended to begin with, it now makes more sense to be well under the legal limit before considering operating a vehicle, thanks to the increased latitude that officers have in testing potentially intoxicated motor vehicle operators.

If for some reason, you are arrested and convicted of driving while intoxicated, the penalties can be severe. The penalty for the first offense includes a mandatory jail sentence of at least 3 days, license suspension for a minimum of three months and a fine of up to $2,000. These penalties escalate as the offenses mount, with a jail term of up to 10 years, a $10,000 fine and up to 2 years without one's license after a third conviction.