On Monday, Uber announced a partnership with the electric scooter rental company Lime. Uber already owns Jump Bikes, an electric bike startup. Lyft just bought a bike rental company as well. All these moves are about creating one-stop shopping for all kinds of transportation and also about solving a pretty basic problem. The average cab ride is less than three miles and using a car to make that trip is expensive and inefficient, especially in traffic. Hence this new investment trend in what's being called micro-mobility. Ralph Buehler is a professor of urban affairs and planning at Virginia Tech. He spoke with Marketplace Tech host Molly Wood about what he refers to as multimodality.