Maria asked:
"How big does a kid have to be to sit in a car's front seat? There are lots of opinions out there ranging from 12 years old, to 16. What is the height and weight we should be looking for to make this transition?"

It's a good question. Remember when Britney Spears drove off from paparazzi with her baby on her lap?

At my request, Tracy Whitman, project coordinator for Maryland Kids in Safety Seats, wrote this reply:

"The Maryland Child Passenger Safety Law does not prohibit children from sitting in the front seat, with the exception of placing a rear-facing child in front of an active air bag. However, Kids In Safety Seats (KISS) suggests that parents follow the safety recommendation offered by the National Highway Traffic Safety Administration. That is, to keep all children under age 13 in the back seat. Currently, there are no weight or height suggestions as to when a child can safely ride in the front seat.

"Because there is no law requiring children to ride in the rear seat, we (KISS) find parents stating that they allow young children to ride in the front seat as a reward for good behavior or it may be viewed as a "rite of passage," when in fact, allowing children under age 13 to ride in the front seat places them in danger.

"There are two main concerns. The first is that front end collisions are the most frequent type of crash. A child seated in the front seat during a crash is at higher risk of injury due to the crash forces. During a crash, there is a tremendous amount of energy generated. This energy is distributed through the crumple zones and vehicle frame, into the seatbelts and then into the body. Injury is cause by the transfer of energy into human tissue. Because adults are larger and stronger, they can typically absorb crash energy. However, because children are smaller and more fragile, they cannot absorb the energy like an adult. If a child is positioned in a vehicle closer to the crash energy, there is a greater chance that a young child may be injured. Simply keeping children in the back moves them further from the energy distribution, creating a safer environment.

"The second concern is air bags. Air bags are supplemental restraints because they are designed to be used with the adult seat belt, for adult protection. Prior to age 13, children have very different body structures. Bone density and muscle tone both have a role in how the body will absorb the energy created by a rapid air bag deployment. Around age 13, children have a body structure that more closely resembles an adult, thus allowing them to withstand the crash better than a younger child.

"A final item to consider before a child is allowed to ride in a front seat is correct seat belt fit. Correct fit is when a child is seated all the way back in the vehicle seat, his/her knees bend comfortably over the edge of the seat, the lap portion of the belt is siting on the hip/lower thigh bones, the shoulder belt crosses over the center of the chest and rests on the clavicle and the child can stay seated upright and "in position" for the entire ride.

"Care givers with questions should contact the Kids In Safety Seats Program at 800-370-SEAT. "

AP Photo of Britney Spears driving by Kevork Djansezian