Four Covina teens suffered broken bones early Sunday when their drunk driver crashed into a tree on Honolulu Avenue after leaving a Halloween costume party, police said.

The teens were taken to local hospitals to be treated for their injuries, but the driver, Eric Corona, 19, of Covina was not injured, Glendale Police Sgt. Tom Lorenz said.

“Officers had to ask if the blood was real or fake because they were in costumes,” he said. “The blood was real.”

Corona, who wasn’t wearing a costume, was arrested on suspicion of felony driving under the influence at about 4:34 a.m. after crashing into a large tree at the southeast corner of Honolulu Avenue and Ocean View Boulevard, according to Glendale police reports.

Corona and the teens had just left a Halloween party in Pasadena when they crashed, Lorenz said. The names of his female passengers, three 17-year-olds and one 19-year-old, were not released.

The group believed they were in Pasadena, not Montrose, he added.

Three of the four passengers were able to escape the mangled Toyota Corolla following the crash. One, however, remained trapped, Lorenz said.

Firefighters had to cut the 19-year-old out of the front passenger seat, he said. She had dislocated her left hip and broke her left arm, and was transported to Glendale Adventist Medical Center.

One 17-year-old also suffered a broken arm, while another girl sustained a compression fracture and was bleeding from a large cut on her head, according to police reports.

Both were also transported to Glendale Adventist.

Police found the remaining passenger laying on the ground and moaning from pain, according to reports. She suffered from a cervical spine fracture and was taken to Verdugo Hills Hospital.

“That accident is a very good example of what can happen when we mix alcohol with driving,” Traffic Bureau Lt. Stephen Robertson said.

Police are planning to ramp up drunk driving enforcement in the coming weeks after seeing an increase in DUI-involved traffic collisions on Fridays and Saturdays, he said.

Drunk driving arrests have increased from 494 from January to September 2010 to 538 for the same period this year, according to the latest crime statistics.

Glendale and Burbank police on Saturday scoured the city as part of the Los Angeles County law enforcement anti-DUI “Avoid the 100” campaign, according to Sgt. Michael Glassick.

During their patrols, they arrested six drivers on suspicion of driving under the influence of drugs or alcohol, Glassick said.

Another three people were arrested in connection with driver’s license-related violations, while two others were arrested on suspicions of narcotic and warrant offenses, he said.