At the Gudu junction where the expansive main road of Abuja’s business district ends, dozens of yellow three-wheeled rickshaws have commandeered a portion of the highway, jostling to pick up commuters heading into the suburbs at the close of work.

But Nigeria’s capital plans to ban an essential mode of transport for its millions of poor citizens because of the role authorities say they play in a crime and kidnapping crisis that is engulfing the country’s second-richest city.