The officers could face disciplinary action if wrongdoing is found, said Interim General Manager Amir Sedadi.
The porn video was reportedly posted to an adult website showing an officer spanking and fondling an actress.
The report says the actress also spanks a second officer and performs lewd acts in his city car.
Sedadi said in a statement that the department doesn't tolerate inappropriate behavior. He also said the allegations shouldn't be taken as representative of the department's nearly 600 traffic control and parking enforcement officers.
"We are shocked by allegations that individuals performing their duties in uniform would be experiencing inappropriate behavior," said Bruce Gillman of the Los Angeles Transportation Department.
The Associated Press contributed to this report.