Since 2006 Lexus has deployed the advanced Lexus Hybrid Drive utilizing a set of hybrid car technologies found in the Lexus RX 400h/RX 450h, Lexus GS 450h, Lexus LS 600h/LS 600hL, Lexus CT 200h, and Lexus HS 250h automobiles.
HSD technology produces a full hybrid vehicle which allows the car to run on the electric motor only, as opposed to most other brand hybrids which cannot and are considered mild hybrids. The HSD also combines an electric drive and a planetary gearset which performs similarly to a continuously variable transmission. The Synergy Drive is a drive-by-wire system with no direct mechanical connection between the engine and the engine controls: both the gas pedal/accelerator and the gearshift lever in an HSD car merely send electrical signals to a control computer.
HSD is a refinement of the original Toyota Hybrid System (THS) used in the 1997 to 2003 Toyota Prius. The second generation system THS II first appeared on the redesigned Prius in 2004. The Lexus Hybrid Drive system is tuned for increased power and performance along with efficiency concerns; it was introduced on all-wheel drive and rear-wheel drive Lexus models.