The District will resume breath testing for suspected drunk drivers on Friday, city officials announced Tuesday, ending a 19-month suspension of the controversial program.

"It is an important tool in our joint efforts to combat impaired driving and maintain public safety in the District," D.C. Attorney General Irvin Nathan said in a statement. "We are now well-positioned to combat impaired driving."

The District said in February 2011 that it was going to temporarily stop using breath tests to collect evidence of drunken driving after the city acknowledged that nearly 400 people had been convicted using faulty machines.

"As a result of the miscalibration the instruments apparently produced results that were outside the acceptable margin of error to be considered accurate," city lawyers told defense attorneys throughout the District in a 2010 letter.

According to court records, an independent expert warned the city government as early as 2008 that the breath-analysis machines were producing flawed results, but the District continued to use them.

Earlier this year, the city settled a spate of lawsuits that people who were wrongly convicted filed against the District, though D.C. said it reached the deals to save the time and expense of continued litigation.

During the program's lengthy suspension, the city used field sobriety tests and urine screens to evaluate drivers' intoxication levels, and police were still able to arrest hundreds of motorists.

Metropolitan Police Department statistics showed that the agency arrested 633 people for impaired driving in the first six months of 2012.

The resurgence of the breath-testing program will come less than two months after the District began to impose stricter penalties for drunken driving. Under the toughened law, which took effect on Aug. 1, some minimum jail sentences for drunken driving doubled.

The law also upped the maximum penalties for first-time offenders, and judges can now hand down sentences of up to 180 days in jail.

Under the measure, motorists driving commercial vehicles also face a new, lower threshold for a drunken-driving charge. Although most drivers are considered intoxicated with a 0.08 or higher blood-alcohol content, commercial drivers hit that level with a blood-alcohol of 0.04.