Sitting in a reclined position when the vehicle is in motion can be dangerous.
Even when buckled up, the protections of your restraint system (seat belts and air bags) is greatly reduced by reclining your seatback.
To reduce the chance of injuries in the event of an accident and to achieve the maximum effectiveness of the restraint system, all passengers should be sitting up and the front and rear seats should be in an upright position when the car is moving.
A seat belt cannot provide proper protection if the person is lying down in the rear seat or if the front or rear seats are in a reclined position.
WARNING
Hyundai Tucson (LM) 2010-2015 Service Manual: Description and Operation
Description
The Evaporative Emission Control System prevents fuel vapor
stored in fuel tank from vaporizing into the atmosphere. When the fuel
evaporates in the fuel tank, the vapor passes through vent hoses or
tubes to a canister filled with charcoal.
The canister temporarily holds the v ...
Hyundai Tucson (LM) 2010-2015 Owners Manual: Seat belt safety precautions
Always fasten your seat belt and make sure all passengers have fastened their
seat belts before starting any trip. Air bags are designed to supplement the seat
belt as an additional safety device, but they are not a substitute. Most states
require all occupants of a vehicle to wear seat belts. ...