Brief introduction to Crumple zone-Your saviour

Crumple zone is also known as crush space which is a main structural feature of automobiles and railcars.As you know it plays a significant role in passenger safety and safety of the vehicle by avoiding the major damage.It was usually designed by automobile designers which has its position at front which takes the collision impact.Crumple zones usually made up of adequate materials to absorb the impact force by deforming itself and avoid the travel of force into passenger compartment.Usually the bonnet area deforms and absorbs the force.Some racing cars use aluminium or composite/carbon fibre honeycomb to form an Impact Attenuator that dissipates crash energy using a much smaller volume and lower weight than road car crumple zones. Impact attenuators have also been introduced on highway maintenance vehicles in some countries.
A car will be designed to absorb impact force from both fron and rear so it should have crumple zones at both front and rear but crumple zone at front is mandatory and safer.Engine at front also plays a major role.Yesterday I saw the TATA nano megafactories and the TATA nano chief designer said that they had deployed engine at rear and it helped them to increase the crumple zone.I am bit confused on that point.Could anyone explain it?
a CAR WITH ENGINE at front has better crumple zone or a car with engine at rear?