Brownsville drivers collide with each other less frequently than drivers in any other Texas city, according to the fifth annual Allstate America's Best Drivers Report, released in July.

Whether it's because drivers here are more skilled, or less insured, than the rest of Texas isn't clear. And while you'd think safe driver status equals low insurance rates in the eyes of insurance companies, it's not necessarily that simple.

For the past three years, Brownsville has topped t- he list of the state's safest drivers. This year the city is ranked as having the 23rd safest drivers in the nation -- a two point slip from last year, though it still puts Brownsville ahead of 24th-ranked Omaha, Neb. Brownsville's nearest in-state contender, McAllen, ranked 39th, though Texas border cities tended to rank high compared to cities farther north in the state.

The report, which rates the 200 largest U.S. cities, bases its rankings on the volume of insurance claims per capita a given city's drivers generate. Brownsville, per capita, generates the lowest number of claims of any other Texas city on Allstate's list.

One possibility is that Brownsville drivers truly are more skilled at avoiding collisions than drivers elsewhere. Another possibility is that the city's relatively high rate of uninsured motorists means fewer claims are being filed because fewer people carry auto insurance and couldn't file a claim if their lives depended on it.

Jerry Hagins, spokesman for the Texas Department of Insurance, says the agency doesn't have estimates on the number of uninsured drivers in different parts of the state.

"We haven't seen any regional data on uninsured," he says. "We anticipate having that sometime this year because of a new database. Up to this point we've had to rely on a statewide estimate. We can only conjecture whether it's higher down here."

An estimated 4 million cars -- roughly one in five -- are on the road in Texas without insurance. The state launched the TexasSure Uninsured Motorist Verification System last year to weed out uninsured drivers via a statewide database, though establishing the program has taken longer than anticipated.

The Texas Department of Public Safety, in 2008, issued 2,725 violations and 2,806 warnings in Cameron County to motorists without proof of insurance. Cameron County's 2007 population, according to U.S. Census Bureau estimates, was 384,905. In Collin County, part of the Dallas/Fort Worth Metroplex and nearly double Cameron County's population, DPS last year issued 3,333 violations and 740 warnings.

In any case, "safest driver" designation and low claims frequency doesn't necessarily translate automatically to lowest rates -- though it doesn't hurt, says Kristen Beaman, spokeswoman for Allstate.

"Frequency of claims is just one of many, many factors," she says. "There are so many things that go into it."

Factors insurance companies pay close attention to in setting base rates are "severity" of claims, or how much the insurance company has to pay to fix your car after an accident, likelihood of catastrophic weather and any type of fraud, including auto theft.

When states set up insurance verification programs like TexasSure, they're usually sold as a way to fight high insurance premiums. However, Beaman says a high incidence of uninsured doesn't exert much upward pressure on rates in general, though it does make it more expensive for individual policyholders who feel compelled to add coverage to protect themselves against uninsured drivers.

The good news is that Cameron County appears to have a good mix of factors, since auto insurance premiums aren't the highest in the state, though they aren't the lowest, either. A married, male driver between 25 and 65, with good credit and no violations, pays an average annual auto premium of $477, compared to $503 for his Dallas County counterpart buying the same coverage.

The average was calculated using DOI's list of 35 companies that sell auto insurance in Cameron and Dallas counties.

The city of Dallas has the 17th safest drivers in Texas and the 173rd safest drivers in the country, according to Allstate. At the same time, DPS last year issued a paltry 831 violations and 260 warnings to non-insured drivers in Dallas County, which had an estimated 2.4 million population in 2007.

The bottom line is that, even with what appears to be a higher rate of uninsured drivers than other parts of Texas, Cameron County enjoys some of the lowest auto insurance rates -- though not the lowest. And a good showing in Allstate's safest drivers report isn't enough by itself to nudge rates down further, Beaman says.

"It's got to be a really long-term trend," she says. "It can't be just a couple of good years."