WASHINGTON — Child car seats would for the first time have to protect children from death and injury in side-impact crashes under regulations the government is proposing.

The National Highway Traffic Safety Administration seeks to upgrade standards for child seats for children weighing up to 40 pounds to include a new test that simulates a side crash. The agency estimates the standards will prevent the deaths of about five children and injuries to 64 others each year.

NHTSA Acting Administrator David Friedman was scheduled to announce the proposal Wednesday.