Rover Front Bed keeps the astronaut in the rover.
The cargo bed is in front. Solar power is on the vehicle. The driving position is one of a kind: not seated, and not standing.
Lunar gravity is about one-sixth of Earth gravity. Mass does not change, so momentum does not change. An astronaut in heavy gear can be thrown clear of an open rover. This driving position is built to stop that, and to make getting in and out much easier.
No rover has been built. Range and load numbers come from the prototype, not from a guess.