Regular mobility scooters work perfectly fine on smooth road surfaces. However, rough roads and challenging terrain are unmanageable for the tools. They struggle in such conditions, and worse, they may even end up damaged.
Off-road mobility scooters will nonetheless not be deterred by such roads. They will take on rugged terrains with ease since they are designed with such a purpose in mind. You may find them with more powerful engines and better, larger tires. Ground clearance may also be more in these scooters.