Comment by nine_k

Cars specifically dissipate energy on deformation of the tires; this loss is irreversible at any speed, even if all the bearings have effectively zero losses (e.g. using magnetic levitation).

A train spends much less on that because the rails and the wheels are very firm. A maglev train likely recuperates nearly 100% of its kinetic energy during deceleration, less the aerodynamic losses; it's like a superconducting reversible circuit.