The bridge has cameras and sensors that will mechanically enforce axle load limits.
Engineers are undertaking soil tests to help inform the final design of the overpass.
This is part of the Trans-African Highway, which comprises a network of road projects.
Since February 2014, Kenyans have eagerly waited for the launch of the project.
Construction of the cable cars system is expected to begin in December.
Top Washington official tours Nairobi to inspect U.S. funded projects.
The 77 kilometre road will be upgraded from gravel to bitumen standard.
The Chinese are using the hanging basket technique to tackle challenges.
Work was expected to begin by end of this month and tenders had already been floated.
The project is aimed at curtailing the number of accidents along the dangerous spot.