By Joseph Warungu
BBC Focus On Africa magazine
Mumbi Muriuki is an amazing driver.
The taxi drivers can all be centrally monitored
Not only does she run a taxi company in Nairobi with a fleet of more than 30 vehicles, but also when she leaves her office in the central business district of the Kenyan capital she miraculously gets into all of them as they drive to their different locations to pick up or drop off customers.
At the touch of a button, she can tell which among her flock is low on fuel, which has a hangover and is shuffling at a painful pace, which has gone astray, and which has been car-jacked.
In that case - by another touch of the button she can easily bring it to a halt - much to the horror of any gun-wielding temporary proprietor.
How does she do all this? Kenyan muti or juju? Not at all.
Actually, Mumbi's magical wand is a simple tool of modern day sorcery: a GSM (global system for mobile communications) phone.
Misuse of vehicles
Mumbi's Dial-a-Cab company is one of 20 fleet firms in Kenya which have adopted a new vehicle-tracking technology that has been made possible by the growth of mobile phones.
The brains behind this new technology are two young IT enthusiasts, Paul Mahiaini and Waweru Kimani.
"We saw a gap in the market with fleet owners having a huge problem monitoring their vehicles," says Mahiaini, who acts as marketing director of Stoic Company.
"Misuse of vehicles by drivers is common, as is fuel theft, and fleet owners in the past relied on drivers to tell them the location of each vehicle.
"So we developed this new tracking technology which enables companies and individuals to monitor their vehicles in real time on the internet using the mobile phone network."
At a one-off cost of 40,000 Kenya shillings ($570, £295) and a monthly charge of 3,000 shillings ($40), a transponder is installed discreetly on the vehicle.
This device captures information such as when car doors are opened, how long the car has stopped, and vehicle speed and location.
Through a built-in mobile phone sim card, the transponder continuously relays the data back to Stoic's main server and the control room of the fleet company via the mobile phone network.
All a fleet manager like Mumbi needs is access to the internet to track her vehicles and drivers' movements.
"This technology has brought big benefits to our company," she says.
"We now run our cars more efficiently and save on fuel. Drivers no longer need to return to base in the city centre after each trip - we can see where they are at any time and allocate work close to them.
"We've managed to drastically reduce the running costs of our vehicles and improved on the safety of our drivers and customers because we can remotely demobilise any car that's been hijacked."
It also enables fleet managers like Mumbi to create a speed limit and geo-fenced area - a virtual parameter, for example, of the Nairobi district - beyond which her vehicles should not travel.
Any car that breaches this boundary or speed limit or deviates from an agreed route automatically triggers an alert which is monitored by Mumbi or Stoic.
But not everyone has embraced the GSM-tracking technology.
In one company, all the drivers walked out on the fleet owner after he installed tracking devices on the vehicles, objecting to what they saw as intrusive "Big Brother" technology.
For Kimani it is not hard to see why his company's initiative has met stiff resistance from many drivers.
"Some of the haulage truck drivers thrived on the unmonitored world," he says.
The GPS tracker has caught out dishonest drivers
"One company told us how some of their truck drivers, ferrying transit goods from the port of Mombasa to landlocked countries like Uganda or Rwanda, would spend about five days in Mombasa and inform the fleet managers that they were being held up in the queue at the port waiting to load their cargo.
"But what they were actually doing was transporting other people's goods from the port to nearby warehouses and pocketing the money - sometimes as much as 90,000 Kenya shillings ($1,300) for each driver. Our tracking system ended this misuse of vehicles."
The tracking technology could kill another luxury - African time.
"Fleet companies running on our tracking system have gained a reputation for reliability and predictability from their clients," says Kimani.
"The days when drivers in Kenya would say to their Ugandan clients, 'I'll deliver your goods in Kampala in the course of the day or within the next two days,' are gone. Now one can clearly see where the vehicle is, how fast it's travelling and work out when exactly it should arrive at its destination."
Stoic has also inadvertently strayed into another sensitive area in people's lives - the family.
Some individuals have had tracking devices installed on their family car so that they can be monitored when they drive through dangerous areas, especially at night. But it could turn out to be a doubled-edged sword - Stoic's tracking system and the detailed digital map of Nairobi and other big towns record not just where and when you drove but can pinpoint exactly which house you visited.
"Some men tell us to monitor them as they drive their families through remote areas but are less keen to be 'watched' when alone during their free time," Kimani says.
Mumbi, however, is content with being the woman behind the wheel of every Dial-a-Cab taxi in all her walking, waking and sleeping hours - the laptop her steering wheel, the mobile phone her gear stick.