Pickup trucks have been required to have air bag turnoff switches since 1998.
Government safety experts recommend turning them off when children are riding up front, but smaller children could be hurt, even killed, by the force of an air bag deploying.
The survey found drivers with children aged one to 12 were leaving passenger side air bags switched on 48 percent of the time.
The poll was conducted in 2000 by the National Highway Traffic Safety Administration. An agency spokesman could not say why it wasn't released until now.