The first time the tricycle was introduced to my birth city in Aba located in Eastern Nigeria, I was still much younger then. Everyone in general didn't embrace the idea, bikes where the ultimate then and people questioned the efficiency of the tricycle (usually called keke here) It operates with only one wheel at front and couldn't go long distances. Parts where rare then and import duties where high then, Many other reasons which I can't laid down here.
But with time these reasons became obsolete and lost credibility, reasoning came in and benefits where seen. The tricycle was a good and convenient means of transportation between short distances within the city when there where rainstorms, unlike the bike which didn't have a cover. The tricycle seemed to obey Traffics more , while the bike always had to cut through. Sometimes causing little havoc.
When compared to the taxi in my resident city, the tricycle loads on passenger and gets on the road faster, and without much qualms. These reasons much or less where really handy, now every part of the city and even in semi Urban areas it operates.
Note that reasons and stats changes in different Nigerian cities,off which some don't have a tricycle or bike... Just taxis
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