SPRINGFIELD — The state’s top justices will be keenly interested in a unique mode of transportation when they hit the road next week for oral arguments.The Illinois Supreme Court will hear a case geared around gasoline-powered bicycles when its members visit the University of Illinois in Urbana-Champaign to close out arguments this month.The bikes are part of a due process challenge that argues a statute exempting “low-speed gas bicycles” from the definition of “motor vehicles” under …