Patricia Herndon isn't being too cautious by strapping her 5-year-old daughter into a booster seat, she's abiding by a law that will soon take effect.

"Motor vehicle crashes are the leading case of injury and death to children in Michigan and nationally," said Jeff Spitzley, Coordinator of Safe Kids Michigan

And that's why the current law mandating only car seats for kids under 4 is being expanded for children between 4 and 8 and less than 4'9'' to have a booster seat. Spitzley says seat belts don't lay across the strong bones of kids under 4'9" -- increasing the chances of a deadly disaster.

" The seat belts can cause abdominal organ injuries and also spinal injuries because of how the belts are on their body," Spitzley said.

Parents who don't abide by the law will face consequences.

" They'll be something in the neighborhood of a $65 expense for violations," Spitzley said.

Sen. Michelle McManus (R)-Lake Leelanau is the prime sponsor of the new law that she began working on when her personal experience with her daughter prompted legislative action.

" She was not big enough, I thought, to sit in the back seat with simply a seat belt," McManus said.

But Spitzley warns that the booster by itself still isn't enough.

"You must always use it in combination with the lap and shoulder belt," Spitzley said.

Because upper-body restraint is sill essential and come July 1 the law will be too.