One major component of highway upgrading involves greening the road due to emission and other environmental factors related to the new development. During road construction, the landscape changes and in some cases trees have to be uprooted to give way. During or after the new road is completed efforts are put to ensure that along the highway we have some vegetation. The focus is usually done while no major efforts are invested in greening communities near the road.
Very little efforts are employed to ensure that neighbouring communities are also greened. Outering Rd neighbour communities with less vegetation like, Kariobangi, Umoja, Mathare and Mathare North. The contractor and government agencies concerned should also invest in tree planting in this neighbourhood given that they carry high population and they will be affected by the high numbers of cars that are expected to use the road.
Space is an issue in these place but more trees could be planted in schools, raparian lands and religious institution to help improve air quality in these densely populated communities.
Obstacles to Implementing Green Highways (http://www.astm.org/SNEWS/SO_2008/bryce_so08.html)
Before any new technology can be introduced in society, it must be verified by a consistent history and accepted as safe for use. Most techniques that will lead to the creation and implementation of a green highway system are very young. Standards and research will aid in the development of a track record for technologies, but implementation of technology requires performance assurance.