The first responsibility of engineering is to design safe steering and suspension systems. Each component must be strong enough to withstand and absorb extreme punishment. Both the steering system and the front and the rear suspension must function geometrically with the body mass.
The steering and the suspension systems require that the front wheels self-return and that the tire rolling effort and the road friction be held to a negligible force in order to allow the customer to direct the vehicle with the least effort and the most comfort.
A complete wheel alignment check should include measurements of the rear toe and camber.
Four-wheel alignment assures that all 4 wheels will be running in precisely the same direction.
When the vehicle is geometrically aligned, fuel economy and tire life are at their peak, and steering and performance are maximized.