Many people in the so-called upper class
think traffic police and matatus should be pushed off the cliff. In their view,
traffic police and matatus make worse Nairobi’s traffic gridlock. But last week
we had a chance to experience how commuting would be without traffic police or matatu.
Simply put, for the “orderly and efficient” functioning of the city of Nairobi,
traffic police and matatus matter.
Two decisions; asking the police to stop
controlling traffic at intersections and increasing monthly levies charged to
matatus inflicted anguish and frustration, to say the least, to residents and
businesses who live and operate in Nairobi.
Nairobi County is trawling for revenue. And
governor Kidero believes that policemen caused more confusion and gridlock at
intersections, exacerbating traffic congestion. But this is a very simplistic
reading of a complex problem.
In the typical Kenyan way, without analysis or
evidence or consultation, we plunged into action. We got traffic policemen off
the roundabout believing that traffic lights would work miracles. The result,
one of the worst traffic gridlock ever. It was total collapse of mobility. All
the major roads leading into and out of the city were chocked.
Consider that a vehicle coming into a roundabout
with five roads radiating from it junction could turn one of four ways, with
the widest being a 270 degree turn across two sets of light signals. You can
bet that even the most sophisticated traffic signal cannot handle this
efficiently. All it takes is poor judgment and lack of courtesy on the part of
handful motorists at a roundabout to shut down the entire city. And they did.
Another reason why the network collapsed without
policemen is because the system of traffic signals at most intersections are
the fixed or static time control type. They are based on timers that have invariant
intersection timing and phasing plans. What policemen bring to a static system
is dynamic control. Policemen, in their limited way, adaptively alter phasing
and timing in response to prevailing traffic conditions as best as they
understand it. One of the great features of the dynamic police control system
is that it can respond robustly to random incidents causing unusual demand at a
roundabout.
Using a roundabout to manage road
intersections becomes doubly complex with high vehicle density. Even in the
best of times, without incompetent or discourteous drivers, a roundabout is
difficult to maneuver. Invariably, a roundabout disrupts free flow, amplifies
impedance thus exacerbating snarl-ups in rush-hour traffic. In my view the
roundabout is an inconvenient monument, which presents a problematic structural
constraint to efficient management of traffic flow in Nairobi.
Last Wednesday matutu operators flexed their
muscle by withdrawing their services to protest new parking levies. Whenever
they strike, matatu operators also harass other motorists hence disrupting overall
traffic flow. But the magnitude of traffic gridlock that ensues is associated
with the matatus strike always astounds me. Why is there such a strong
correlation between massive traffic jams and matatu operators’ strike? It seems
counter intuitive because the expectation is that there would be less traffic,
especially because matatus are off the streets, something we always long for.
In my view, this is what happens. Without
the convenience of public transport, nearly all commuters who have cars will
bring them out to the streets. My estimate is that one out of seven people who
take public transport have a personal car but elect to take public transport to
work. Hence, whenever matatus withdraw their services, there will be 2 private
cars for every 14-seater matatu. All you have to figure out is how many people
commute by matatu and how many matatus operate in the city of Nairobi. And it
will scare the hell out of you how many private cars could potentially pour out
into our constrained road network whenever there is a matatu strike. And rain, especially morning showers, also has the effect of getting lots of cars on the streets, just like end of the month when most private car owners love to flash their pay.
Without a publicly funded transit system,
with modern high occupancy vehicles, we are stuck with the cargo minivans. But
I must add that the proposed parking levies are provocative regressive taxes,
which could make things worse for all commuters. Matatu operators offer a vital
public service and must be treated with respect.
How about a combination of 4-way
intersections, underpasses and overpasses, instead of the roundabout? Then we
can keep the moronic static light signals and tell the police to stop messing
around with traffic at intersections.
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