  The more people commute by bicycle, the higher is the number of cyclists
using their smartphones while cycling and compromising traffic safety. We have
designed, implemented and evaluated two prototypes for smartphone control
devices that do not require the cyclists to remove their hands from the
handlebars - the three-button device Tribike and the rotation-controlled
Brotate. The devices were the result of a user-centred design process where we
identified the key features needed for a on-bike smartphone control device. We
evaluated the devices in a biking exercise with 19 participants, where users
completed a series of common smartphone tasks. The study showed that Brotate
allowed for significantly more lateral control of the bicycle and both devices
reduced the cognitive load required to use the smartphone. Our work contributes
insights into designing interfaces for cycling.
