The Prime is a plug-in Prius that can usually drive about 23 miles on electricity only. However, the gas engine tends to start up in cold weather and under full-throttle acceleration. It takes two hours to charge the Prime through a 240 volt connector, and five hours on regular 120 volts. When not running in EV mode, the Prime operates much like the regular Prius, alternating between electric and gas power, returning 50 mpg overall. With slightly altered styling than the regular Prius, the Prime is can hold only four passengers, and it loses the rear wiper. The infotainment system, with its large touch screen, is unintuitive to use. Ride and handling are quite similar to the regular Prius, with responsive handling and a compliant ride. Standard safety features include automatic emergency braking and lane-keep assist. All 2020 models get standard Apple CarPlay compatibility, two USB ports for rear-seaters, and a standard three-passenger rear seat (the previous models only had a two-person rear seat). For the model year 2021, the Toyota Safety Sense system has been upgraded to TSS2.0. This suite of safety equipment includes forward collision warning, automatic emergency braking with low-light pedestrian and daytime bicyclist detection, lane departure warning and lane keeping assistance, automatic high beams and road sign assist. A version of lane keeping assistance (lane tracing assist) helps to keep the car in the center of the lane while the adaptive cruise control is being used. Adaptive cruise control is standard with the stop and go function.