KENTWOOD, MI -- Until Wednesday, local police had only heard stories about people overdosing in vehicles while driving down the road.

But it happened in Kentwood when a Kent County sheriff's deputy came upon a car blocking traffic at Shaffer Avenue and 28th Street at 11:30 a.m.

The deputy found three unconscious people inside and quickly suspected they had overdosed on heroin. They were saved with doses of naloxone, a reversal drug that blocks opioid receptors.

Kent County Undersheriff Michelle Young said the situation was unusual.

"We have seen what we believe were people that pulled off the road to get stoned, but nothing like this," she said.

"When people are willing to take that level of risk, you've gone pretty far," she said about addiction.

Young believes the discovery only confirms her suspicion that the heroin epidemic is worsening in West Michigan.

"We've been pushing the story about the heroin problem for 18 months now. But it's still increasing. We're still seeing the problem grow and it's getting more significant," she said.

Young said heroin causes people to become addicted very suddenly and it can take years of treatment to become stable.

She describes the addiction as something that is "treatable" but not necessarily "curable."

The three people found unconscious Wednesday were two women, ages 31 and 32, and a 40-year-old man. They are all from Greenville.

The driver, one of the women, was arrested after she was released from the hospital.