Simplify the following text for a Grade 11 native English-speaking person.
Original: The Beetle was popular in less-developed areas of the world because of its rear-mounted air-cooled engine , flat floorpan , and rugged torsion bar suspension .
Simplified: The Beetle was popular in places with few roads because of its rear-mounted air-cooled engine , flat floorpan , and torsion bar suspension .