Within hours of new legislation going into effect that nearly triples prison terms for those convicted of vehicular homicide, a 31-year-old Federal Way woman allegedly caused a fatal crash a week ago after mixing prescription drugs with pink Champagne.

Michelle Leigh Dittamore was charged Wednesday with vehicular homicide, accused of slamming her father's two-seat sports car — which she didn't have permission to drive — head-on into a vehicle driven by Jana Lynne Berry, 48, who was killed instantly at the scene of the June 7 late-night crash.

Dittamore, who spent nearly two days at Seattle's Harborview Medical Center, was booked into King County Jail on Saturday, where she is being held in lieu of $250,000 bail, according to court and jail records.

Dittamore's 4-year-old son, Grayson, was in the front passenger seat and suffered bruising from the seat belt and air bag, according to charging documents. His presence in the vehicle at the time of the crash is considered an enhancement that, should Dittamore be convicted, will add a year onto her prison sentence.

Dittamore was driving in Federal Way just after 11 p.m. when she allegedly crossed the centerline on Pacific Highway South and collided head-on with Berry's 1993 Honda Civic, charging papers say. The force of the collision caused Berry's car to spin around, and it was struck broadside by another vehicle, the papers say. Berry died instantly.

Witnesses and police officers found Dittamore still in the driver's seat. A drug recognition expert observed that her "speech was slow, thick-tongued and slurred," and that Dittamore "would stop talking in the middle of sentences" and insisted her son was with his father, charging papers say.

Dittamore had allegedly consumed one tumbler of pink Champagne and the drug Klonopin, a benzodiazepine, which is known to make users dizzy or drowsy, before the crash, charging papers say. Her prescription for Klonopin, along with her father's prescription for Ambien, a sleep aid, were found in Dittamore's vehicle, the papers say.

Dittamore, whose license was suspended in 2009, apparently sneaked into her father's bedroom and took his car keys along with his Ambien prescription, charging papers say. She didn't have permission to drive her father's Honda S2000, nor was she insured to drive, the papers say.

In March, Gov. Chris Gregoire signed into law a bill that increased prison terms for those convicted of vehicular homicide to six to 8 1/2 years, an increase from the previous 2 ½ to almost 3 ½ years. The law went into effect on the day of the crash.

Sara Jean Green: 206-515-5654 or sgreen@seattletimes.com