Few years back when the pressure of upgrading of capacity of existing highways due to reduced level of services was felt due to rapid increase of vehicles on the road , we were having two choices before us - either to widen the existing highway's  lanes to more numbers of lanes within existing RoW or go for combination of elevated portion and bypasses .
But carrying out the upgradation by way of the same has not only created situation difficult for those areas where widening was taken but also construction of elevated in city portion / habitation was costly also . Apart from the same dismantling existing houses in the habitation portion is highly resistant from public and also costly . The time in terms of hindrances always led to time and cost run of the project .
The above constraints has led us to go for rethinking for development of highways afresh between economic zones  and smooth flow of traffic through greenfield.In greenfield at a time the cost of land is also less and at the same time the highway can be planned in a better way with no constraint of row . Also the alignment can be planned to cross in shortest way and through new underdeveloped villages giving them to prosper .
Many other factors involved has now led to development of many greenfield expressway which are now becoming reality under prestigious BHARATMALA project .