What you call dispatch abroad is jaluo kind of guy - who take a cut for every job - brokers - ya mzigo - there is one jaluo at chinese ceremic that I had to pay 50k - mombasa is full of brokers - or clearing/forward. Those are ONLY PEOPLE making money.
Yes road construction has money as long as you get a good driver who wont cause gear/engine damage.
Generally it very tough business. It's better to invest in treasury bonds and real estate...or open a petrol stations...anything that has very few risks.
Pundit in Kenya the best way to make money in trucking is to get those 6 or 10 wheeler and either put a tanker or tipper trailer then get into road construction either delivering water or road construction materials from soil to Kokomo especially with the Chinese. Of course you might have to grease those roads engineers to get it. Your only expense is driver and maintenance. Fuel they take care of it. Your truck does very short trips so breakdowns are minimal. You can take home anywhere from 3 to 500k shillings depending on the deal. I have this jaluo jeuri engineer friend of mine who takes 50k from each truck monthly where he is the supervisor.