Topeka ? Bills to punish parents who don’t put their young children in booster seats or who leave them alone in vehicles moved through a Senate committee Tuesday, a week after the House approved them.

On unanimous voice votes, the Transportation Committee sent the measures to the Senate for debate, which could occur later this week. Both have the backing of law enforcement agencies, public health officials, child welfare advocates and Gov. Kathleen Sebelius.

In recent years, such support hasn’t been enough to overcome opposition from conservative legislators in the House who fear such changes can’t be enforced and would infringe too much into families’ lives. The Senate approved booster seat bills in 2001, 2002, 2004 and 2005, only to see them die in the House.

That history made last week’s House action significant. More than 30 House members who had opposed the booster seat bill in 2005 supported this year’s measure.

“It saves lives,” said Senate Transportation Committee Chairman Les Donovan, R-Wichita. “It saves many, many terrible injuries.”

State law requires children under 4 to ride in child safety seats and mandates that children age 4 through 13, drivers and front-seat passengers wear seat belts. But safety advocates say they have learned that without booster seats, belts often don’t fit young children properly and can injure them severely in a crash.

One bill endorsed by the Senate Transportation Committee would require children ages 4 through 7 to ride in booster seats if they weigh less than 81 pounds or are under 4-foot-9. The bill would triple the fine for violating the law from $20 to $60.

The Senate committee removed a provision under which out-of-state drivers would have received only warning tickets.

The other bill makes it a misdemeanor for a licensed driver to leave a child under 9 in a car without someone who is at least 13 years old. The fine for a first offense would be $25; it would be $250 to $500 for a second offense within three years.