State data are showing that the number of uninsured drivers in Texas has dropped significantly in 2012. But how much of that trend can be attributed to greater compliance with mandatory car insurance laws, and how much of it can be chalked up to data fluctuations?

In October 2008, Texas law enforcement and state officials got their first access to a new state-run database, called TexasSure, that was constructed to help crack down on the problem of uninsured drivers on the state’s roads. TexasSure worked by taking vehicle registration data and matching it up with insurance records provided by the state’s coverage providers. If a car has matching registration information in the database but no matching policy info, officials assume that it is uninsured, and the vehicle owner may end up getting a letter in the mail asking him or her to verify that the car is in fact covered by an active policy.

The first publicly available data from the program was released in November 2009. It showed that there were about 4.13 million unmatched registrants—22 percent of all registrants. But by the end of May 2012, the total number of unmatched registrants came in at about 2.58 million—about 13 percent of all registrations. So was the drop of 9 percentage points attributed to stepped-up enforcement and greater public awareness of the implications of driving uninsured?

That’s likely to have had something to do with it, but what shouldn’t be overlooked is the fact that between November 2011 and February 2012 the database got a major facelift that weeded out what appears to be a significant amount of obsolete data. This helped clean up the database and wipe out a significant number of erroneous records, according to The Associated Press.

“A main source of erroneous information involved drivers who sold or traded their cars, with those vehicles being shown in the TexasSure database as registered to the original owners but without any insurance coverage,” the AP reported.

Jerry Hagins, a spokesman for state insurance regulators, told the AP that his office couldn’t quantify how much of the decline should be attributed to the data cleanup and how much should be attributed to more drivers being insured.

Now, to give Texas officials credit, there may very well have been enforcement and compliance developments that contributed to the higher rate of matched registrants. A handful of cities have started launching insurance checkpoint campaigns to catch motorists trying to skirt the system, and the database cleanup would help get mailed uninsured notices to the right people.

But going from a 19.93 percent unmatched rate before the cleanup to a 15.23 percent rate after makes it seem like the cleanup had a lot to do with it—especially considering the fact that the rate had hovered between 22.16 percent and 19.71 percent for the 2.5 years before the data fix.

Another factor making it difficult to assess the true uninsured rate is the fact that the number of total registrations can fluctuate pretty significantly between data periods. For example, in the three times the state released TexasSure data between November 2011 and May 2012, the total number of registrations dropped from 19.41 million down to 18.39 million and then shot back up to 19.76 million.

But regardless of whether the uninsured motorist rate in Texas can truly be measured accurately, the important takeaway for drivers in the Lone Star State is that they should never get behind the wheel without car insurance in Texas. The reason officials require residents to carry coverage is if they cause an accident, they need to be able to pay for all the damages they cause, and purchasing auto insurance is the easiest way to do that. If drivers don’t purchase coverage and get caught on the road, they could have to pay between $175 and $350 in court fines for a first offense. Penalties for further offenses can result in court fines of up to $1,000, license suspension, and vehicle impoundment, according to a guide from Texas regulators.