The chairman of the Senate transportation committee on Wednesday asked Transportation Secretary Ray LaHood how his agency plans to address delays in regulating car seats for older children and those over 65 pounds.

In a letter to LaHood, Sen. John D. Rockefeller IV (D-W.Va.) said he was surprised to learn in a March 14 Washington Post story that seats for children over 65 pounds have no government safety standards, because the government has yet to develop an accurate child-size crash test dummy. A 2002 federal law required that the 78-pound dummy be developed by 2004.

Rockefeller said that delay and the fact that a lack of test dummies has also left no government standards for side-impact protections in seats for infants and toddlers “are of real concern to me.” Rockefeller praised LaHood for his attention to safety issues and said he wanted to know by April 20 what the department will do to ensure that seats for older children provide proper protections.

The National Highway Traffic Safety Administration has said it cannot set standards for child safety seats unless it has accurate child-size crash test dummies to ensure that manufacturers are meeting them. The child dummy being developed has had problems accurately measuring the amount of force that seats allow on the dummy’s head.

Manufacturers have begun making seats for children over 65 pounds because more children are overweight and many parents want their children in a harness car seat or belt-positioning booster seat as long as possible. Manufacturers have said they ensure safety-seat protections via their internal testing.