“I know people love to say parents know best, and in this case, it’s 100% true!
Depending on the type of accident, your legs could get crushed, or you might not be able to get out of the vehicle. If the airbag deploys, this could push your legs into your body and cause serious or fatal injuries.
Your mom is likely aware of the dangers when she says not to put your feet on the dash. Although it can seem unlikely that you’d get into a car accident, you never know.