2011 Toyota Prius Owners Manual - Page 270

2-4. Using other driving systems n Turning the LKA system on The lane departure warning function and lane keeping assist function will be automatically activated depending on the recognition condition of lane markings, vehicle speed and the setting of radar cruise control (vehicle-to-vehicle distance control mode). Press the "LKA" switch to activate the system. Press the switch again to turn the LKA system off. ITO24P132 244 PRIUS_U (OM47685U) DVD