The comments have good ideas to solve the traffic menace. Allow me to throw my peni mbili into mix. We have too many vehicles heading into the CBD. However, banning private vehicles will not solve this traffic problem. We all know what happens when it rains and you are using matatus. Think of those watotos who have to wake up at 4/5am and have to travel across Nairobi so that they make it to City Road primary by 7am travelling by matatu, earlier if its the rainy season.
Raising the parking fee (a tax on vehicle usage by any other name) will only increase the amount of money that is stolen by Kidero et al. Speaking of parking fee, it should have been ring fenced such that it can only be used on provision of public transport. Sio kulipa madeni ama salary za watu wa kanjo.
For a start, govt/kanjo (KRA returns,driving license applications, birth certificates, passports, land titles, id card applications) will just have to be forced to eat less parking fee by moving its "services" if we can call them that to the estates.Why should you travel to the CBD to apply for a passport, birth certificate, company registration or check out a land title?
Move even the government owned markets outside the CBD (Marigiti, hio ya samaki hapo Koinange)
Matatu routes will also have to be redesigned so that not all matatus end up in the CBD. Why should you go to the CBD if you are travelling from Pangani to Westlands?
If redesigning routes is too politically hot and there has to be a central hub/terminal, place it well outside the CBD.

Ultimately, government owned (not government managed, hii sirkal iko na wazimu) rail based transport would have to come into play, linking the different sections of the city. Central hub iwe mbali na CBD pia. Rail lines designed in such a way that sio lazima kuingia CBD kama you have no business there. Government ownership will ensure that new areas are served by rail even when they are not commercially viable.
Vehicle usage will then be limited to those who have to deliver viazi, mayai na mali zingine to the CBD and those who cannot bear to part with their vehicles. Personal, non business usage can then be taxed via congestion charges, toll roads etc.
This is how big cities all over the world have solved their traffic problems, at the same time spreading development to wider urban areas.

Very interesting debate here..... if i could also add my 2 cents into it think the solution would be a commuter railway as described in the image.

https://pbs.twimg.com/me...R8J06IIAAQkec.jpg:large

Rail 1: Syokimau - JKIA - CBD - Westlands
Rail 2: Kiserian - CBD - Juja
Rail 3: Kiambu - CBD - Rongai South
Rail 4: Kikuyu - CBD - Kitengela

Simply put a "park and ride" system as suggested by a few earlier in the thread....this particular system would solve the issue of mass transportation if run properly. Other factors would be speed, security, efficiency of the schedule and a changed perception of public transport would be the critical keys to success in my opinion.....KPLC would also need to up their game to ensure a constant reliable supply of electricity if the trains used were electric.

hope we get there.

But gava seriously needs to improve rail transport. I looked at some of those wagons za commuters they look so rusty and dirty like kanjo toilets zamani. These middo class and mido class wannabe can never ride such

We're waiting for your well researched paper on the economic effects of discouraging private cars or improving rail transport

And by the way I understand there are cities with extremely high personal vehicle per capita where a family can have as many as three of four cars - with one being used by the house girl/nanny etc to run errands. And this is replicated by a majority of the families.The volume of cars can be crazy. Such cities have no option but to restrict movement especially given that they have efficient and reliable public transport.

Come to Kenya and the number of personal cars is not even at 5% of adult population (let alone the total population) and you cannot come up with a creative solution? Ban, ban, ban!!! Nini hii???