A dual-carriage Mombasa Highway?

We built the new multi-lane Thika Highway to ease traffic, among other reasons. For a very brief while, the traffic did, indeed, ease. But nowadays, at rush hour in the morning or in the evening, the highway is just as congested as it was before. It's an interesting phenomenon: build extra road space to ease traffic, but the problem is only temporarily solved. So now there are loud proposals to convert the Mombasa Highway into a dual-carriage road between Nairobi and Mombasa to "ease traffic". Yes, it is almost five hundred kilometres long so the cost will probably bankrupt the nation. Obviously, those who want a dual-carriage Mombasa Road are being hyperbolic. What they want is to remove the trucks from the road thinking that it is the trucks that are responsible for the slow average speeds experienced on the highway. Just like the Thika Highway, their one solution will probably not solve their problem with the average speed. They will probably need to rethink how the highway can bypass towns and villages, thereby eliminating bumps, and by also imposing a minimum speed for long stretches.