Along with the introduction by the FIA in 2014 of the new 1.6-litre turbocharged V6 'green' engines, the technical regulations also included a new rule allowing teams to use electronic brake assistance on the rear wheels for the very first time. The purpose of this evolution found its reason in the considerable increase in harvesting demands of the energy recovery system (ERS) as well as its increased performance. While F1 cars have used fly-by-wire for throttle input since 1992, the good old brake pedal remained until very recently mechanically linked to the master cylinders and, ultimately, to the front and rear brake calipers. The front brakes still operate this way, but the rear brakes are now electronically controlled in a manner which assesses how much brake pressure a driver has called for in order to slow the car in a consistent way while ensuring the maximum energy harvest for the ERS.