AUSTIN (KXAN) — A KXAN investigation has resulted in a dramatic drop in the number of Hispanic drivers incorrectly reported as “white” by Texas Department of Public Safety troopers.

KXAN’s investigation in 2015 found troopers wrongly identifying the race of minority drivers, mostly Hispanic, during traffic stops. Experts say the errors skew racial profiling reports required by a Texas law in which officers must determine and document the driver’s race.

The most common name of drivers stopped and recorded as “white” by DPS included Garcia, Martinez, Hernandez, Gonzalez and Rodriguez. DPS was forced to admit the problem and promised lawmakers changes to fix it.

To find out if DPS is now following the law, we asked racial profiling expert Frank Baumgartner at the University of North Carolina to analyze traffic stops in 2016.

“The number of people with Spanish surnames who are listed as Caucasian is down to a very low percentage,” says Baumgartner.  “One quarter from what it was before, so I think there’s been a dramatic improvement in the quality of the data.”

The results show our investigation has made a major difference.

In the four years before our 2015 investigation, up to 18 percent of drivers ticketed as white by DPS had Hispanic surnames. After our reports, in 2016 that dropped dramatically to just 4 percent.

Meaning, racial data from DPS traffic stops is now much more accurate. Experts say mistakes like that skew racial profiling reports required by a Texas law in which officers must determine and document the driver’s race.

“We can’t study racial profiling if we don’t have good data on who’s of what race. So it is really good to see the DPS is doing a better job of it,” says Baumgartner.

The more accurate numbers means the number of Hispanics stopped and searched has actually gone up slightly. Baumgartner told Texas lawmakers last fall his analysis of DPS traffic stops shows state troopers are much more likely to search black and Hispanic drivers over white motorists.

DPS denies its troopers racially profile.

Texas DPS troopers’ traffic stops are front and center at the State Capitol as lawmakers are set Thursday to unveil the Sandra Bland Act. It stems from a stop nearly two years ago in which a trooper got into a heated conversation with the driver, Sandra Bland.

The African-American woman was arrested on charges of assaulting a public servant. Three days later, the 28-year-old was found dead in her jail cell, ruled a suicide by hanging. Bland’s death sparked concerns about racial profiling and jail conditions across Texas and the nation.