The government is building 4,120km of roads countrywide.
Thika Road completion has also seen malls being rolled out along the route.
Construction of the Tazara Flyover commenced in 2016 and was completed in 29 months.
KeNHA will wait for MPs to pass laws that will allow the erection of toll stations.
The High Court has stopped the State from acquiring land from the Nairobi National Park.
The project began in 2009 following the award of the tender to China Road and Bridge.
This marks the start of the process of construction of the much awaited bypass.
The facility is the first to be built in Kenya in the last 80 years.
The highway was split into three sections for construction works.
The project, with lighting and a footbridge at the KWS gate, will conclude in 15 months.