The process of development in many countries of the World is characterized by an increase in traffic congestion. This is because most of the developments do generate traffic. Besides, car ownership also increases as income levels increase. However, this does not take place at the same rate as the improvement of the already existing transportation infrastructure. When demand exceeds supply due to more vehicular traffic sharing limited road space, congestion becomes inevitable.

Some of the undesirable consequences of congestion include: Longer travel times, wastage of fuel, increased air pollution due to carbon emissions thus contributing to global warming, emotional and psychological stress of motorists and passengers, inability to respond to emergency situations and spill over effect on primary and secondary distributors. In economic terms, this makes the transport system non-functional as it is contributing to economic stagnation. This is because of a lot of time and labor wasted that is not productive.

This development project therefore presents rationale behind decongestion of Mombasa Road through Grade Separation. This is the best alternative to minimize congestion as it proposes a model where there is expansion of the main carriageway from 6-Lanes to 8-Lanes to increase the capacity to carry more traffic volumes per unit time and limiting access to the main carriageway so as to reduce interference with express traffic. This will however take the form of deliberate use of underpasses, Viaducts (Flyovers), acceleration and deceleration lanes, Service lanes for heavy commercial and industrial developments, pedestrian sidewalks and elimination of all At-grade junctions.

The adoption and implementation of this development project will increase the capacity of Mombasa Road to hold more traffic volumes, increase travel speeds and reduce travel time. The elimination of all at-grade junctions and subsequent replacement of the same with modified separated interchanges will see continuous flow of traffic with no competition between traffic streams moving in different directions. These junctions will cease to be bottlenecks to traffic flow. Mombasa road will thus be relieved of the congestion menace.