SPRINGFIELD — Black and Latino drivers pulled over in Illinois traffic stops last year were more likely to end up with a ticket and have their vehicle searched than their white counterparts, according to a new Transportation Department study.

Minority drivers also were involved in traffic stops at a higher rate than their share of the state population would suggest, even though illegal contraband was more likely to be found in vehicles being driven by whites.

The average length of a traffic stop was the same for all races: 10 minutes.

The American Civil Liberties Union said Wednesday that the study supports its request for a federal civil rights investigation of the way Illinois State Police handles driver searches. It also called on state leaders to address the issue in all police departments.

“It is time for the political leadership in Illinois to act and end this practice on our highways and roads across the state,” said Harvey Grossman, legal director for the ACLU of Illinois.

State police spokeswoman Monique Bond said the agency will study the new statistics as part of an internal review that was launched after the ACLU filed a federal complaint last month. She said it would be weeks before the review is finished. The state police have previously denied any bias.

The new study is the latest annual review of traffic stops by virtually all police departments in Illinois. The 2.4 million stops were analyzed by the Center for Law and Justice at the University of Illinois at Chicago.

Minority drivers accounted for 12 percent more traffic stops than would be expected based just on their share of Illinois’ population.

The study found that 55 percent of white drivers got tickets after being pulled over, compared to 65 percent of Hispanic drivers and 62 percent of black drivers. 

When police asked permission to search a driver’s car without probable cause — something that is rare for all racial categories — it was more likely to be a minority driver. Police used “consent searches” for 0.6 percent of white drivers, compared to 1.4 percent of black drivers and 1.3 percent of Hispanics.

Police were more likely to find contraband material, such as drugs or weapons, in the cars of white drivers, according to the study. The chances were 25 percent for white drivers who agreed to a search, 19 percent for blacks and 13 percent for Hispanics.

Statistics for the state police differed slightly.

Minority drivers were stopped for a median time of 15 minutes and 60 percent received a ticket, the study showed. That’s compared to 12-minute stops for whites, 56 percent of whom were issued a ticket by a trooper.

Although state police rarely use consent searches, minorities were more likely to be searched. Troopers conducted consent searches on 36 out of every 1,000 minority drivers they stopped, but only 12 out of every 1,000 white drivers.