Why do matatus wait to fill up at the terminus?
The Sunday Nation
Nairobi,
19 February 2012
I think I have cracked the mystery behind the reason Kenyans are such poor time keepers. You see, there are two types of processes in life: clock-driven and event-driven.
In clock driven processes, progression from one stage to the next is determined by the time of day. A good example of this is the school time-table; when the bell rings (at the specified time), the teacher leaves the classroom and another one comes in.
In event driven processes, the progression occurs after a certain event has occurred. Most of our processes fall into this category. This is why, forexample we never start meetings on time: we wait for there to be enough people (quorum) in the room!
But the most common event driven process is our public transport. Matatus and buses only leave the terminus after a special event occurs: when all the seats are occupied.
I have often wondered whether this waiting for the vehicle to fill-up makes business sense. In other words, would the vehicle make more money if it operated on the clock? Can the operator set rules for the maximum time that his vehicle should wait for passengers at the terminus?
Suppose the average round trip from the terminus to final destination and back takes about one hour. Assuming that it operates from 5am up to 9pm, this vehicle will do about 16 trips as they are know in the industry.
But that is a bad approximation because it also assumes that the vehicle is all alone on the route. That it doesn’t have to queue for its turn at the terminus. Nevertheless, this fact will not affect our results because we are only concerned about the time spent waiting for passengers during off-peak periods.
Suppose that the average arrival rate for passenger during off-peak periods is one person per minute. This means that it would take about 14 minutes to fill a 14-seater vehicle.
Therefore the time to do one trip increases to about 1.25 hours. Thus in a 16-hour day, the vehicle can do only 13 trips. This means it carries about 182 passengers in total.
If the operator wants to make one extra trip, then the terminus waiting time must be reduced. To do 14 trips in the same 16-hour day, the time per trip must be about 1h:8m (that is, 16 divided by 14).
This means the vehicle leaves with an average of 8 passengers – remember; average arrival rate is one per minute. Thus it will carry 112 passengers (8people multiplied by 14 trips) per day.
Clearly then, this wouldn’t be a good idea – fewer passengers are carried. However, if the vehicle operated on a time table; that is, leaving at specific times only, passengers would soon learn the programme and wait for the next departure.
Thus every trip would have more than the 8 passengers calculated above – perhaps even a full load all the time. Thus the operator would make more money than in the present method of waiting “blindly” at the terminus.
 |
 |