MADISON, Wis. -

Madison police said they arrested two drivers in separate crashes Sunday on suspicion of driving after using heroin.

Investigators said the first incident happened around 5:12 p.m. at the intersection of South Stoughton and Pflaum roads.

A 38-year-old Madison man said he was stopped at the red light when a 23-year-old driver rear-ended his car. The 38-year-old got out of his vehicle to exchange insurance information and said that's when the other driver hit the gas and knocked him over, breaking his clavicle, according to a Madison Police Department incident report.

Police said the 23-year-old driver, Jacob M. Engel, of Oregon, continued driving into the intersection, knocking down a traffic signal pole, and crossed oncoming lanes of northbound traffic on South Stoughton Road, before veering across a ditch and frontage road and crashing into a building.

Engel was taken to a local hospital, where he was treated for minor injuries, police said.

Police said Engel admitted to using heroin and shared that he had just completed a treatment program.

He was taken to the Dane County Jail and faces charges of causing injury while operating a motor vehicle while under the influence and first-degree reckless endangerment, Madison police said.

The second incident happened at 5:27 p.m. in the 600 block of Gately Terrace, which is off Tokay Boulevard on Madison's West Side.

Madison police said they arrested two Dodgeville men after they crashed their car.

Moments earlier, an 85-year-old woman living on Gately Terrace noticed the men had driven their van onto her driveway, and into her flowers. She said she told the men to "get out of here now," according to a police incident report.

Police said the driver slowly pulled away but then went unconscious.

Another neighbor and his 71-year-old father-in-law witnessed the crash, ran to the van and put it in neutral. They rendered first aid until first responders and police arrived.

The driver and his passenger, who also was unconscious, were taken to a Madison hospital, police said.

Chase A. Anders, 21, was arrested on charges of operating a motor vehicle while under the influence and possession of heroin, possession of drug paraphernalia and casual possession of marijuana, police said.

Police said the passenger, Travis H. Novak, 24, was cited for possession of heroin and possession of drug paraphernalia.

Investigators said they found full and empty beer cans in the vehicle, as well as marijuana, needles, a tourniquet and other paraphernalia.