LOS ANGELES, Calif.–The city Department of Transportation has failed to collect an estimated $5.4 million in unpaid parking tickets by not aggressively pursuing ticket “scofflaws,” according to a city controller’s audit released today.

In almost three-quarters of cases in which the department identified repeat offenders illegally parked, the attendant issued a citation instead of calling for a boot or to have the car impounded, the audit found. LADOT also failed to use license plate recognition equipment designed to catch regular parking violators, according to the audit.

LADOT traffic officers have the authority to boot or impound vehicles with five or more unpaid parking tickets. About $18.8 million remains unpaid by vehicles that fall into that category and whose registered owners have been notified they have exceeded the five-ticket minimum for impounding, according to the audit.

The report also found that DOT management effectively disbanded a unit tasked with going after scofflaws.

“This failure to deploy (LPR technology) resulted in a potential revenue loss of $5.4 million and, compounding the problem further, did nothing to promote a change in behavior for these continuous violators,” City Controller Wendy Greuel wrote in the report. “With some offenders receiving up to 20 parking citations, it is not realistic for the LADOT to believe that these scofflaws would suddenly come to their senses and pay their parking tickets simply because another ticket was slapped on their windshield.”

Since she began her audit, Greuel wrote, LADOT has re-established its scofflaw enforcement unit and LPR technology.

“In light of the budget deficit that the city of Los Angeles is facing in upcoming fiscal years, we must ensure that we are enforcing the laws on the books and that no opportunities for collecting revenues are missed,” Greuel said.