The city has more than 400 junctions but just 42 traffic light-controlled junctions with half of the lights using manually pre-fed data while the other half uses an automated intelligent system to allocate time for roads with heavier traffic. Several of these junctions with light either do not work or are manned by police officers.
The lack of coordination between the intelligent systems largely in the western part of Nairobi and the other light-controlled junctions in the central business district — mostly manned by the Nairobi Metropolitan Services askaris — have fuelled the mess that keeps motorists in traffic for hours.
On Ngong Road, where an Intelligent Traffic Control System (ITS) was recently installed, vehicles only move smoothly between Karen and the junction with Hospital Road, thanks to the smart traffic lights along the section. Beyond there, the traffic system in town has no way to tell how much traffic to expect and what time to allocate.
The NMS, Kenya Urban Roads Authority (Kura) and the Traffic Police all have different approaches to keep vehicles moving in the city, which do not link up, creating an endless confusion that causes heavy snarl-ups.
Traffic experts say as soon as the coordination is fixed and human intervention is minimised in the junctions, traffic flow in Nairobi will be made efficient with the lights allowing time to traffic depending on the weight of flow from a given direction.
“For traffic to flow in Nairobi, we need a system that can communicate in all the junctions and all in a shared platform that even the police can use for security monitoring.
“Having one part of the city serviced by an automated intelligent system and the rest of the junctions in darkness manned by people who cannot predict what weight of traffic to expect from a particular road increases the clogs we witness during peak hours,” said Nicholas Airo, managing director and ITS expert at NAS International Holdings behind the smart traffic lights on Ngong Road.
NAS International manages 20 junctions with such traffic lights that use sound and cameras to tell the time to allocate for a particular side of the road on behalf of the Kura.
According to Mr Airo, the use of such systems in Nairobi have proven that junctions can be completely unmanned with the cameras able to record traffic violations and prompt the authorities to trace offending motorists.
The move is supported by traffic management experts within the Ministry of Transport who did not want to go on record for fear of being seen as criticising past initiative by the various state departments blamed for worsening traffic situation in the city.
The experts say the multi-billion-shilling investments in overpasses and road expansions have done little in reducing road congestion given the high rate of increase in the number of vehicles entering the city and the limited space within which the roads can expand.
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