ratios in the "emergency low" mode). Standing starts required the driver to use the clutch pedal. The Self-Shifter first appeared in May 1933 and was offered as standard on the Royale and as an option on the Flying Cloud S-4. In 1937, the four-speed Oldsmobile Automatic Safety Transmission was introduced on the Oldsmobile Six and Oldsmobile Eight models. It used a planetary gearset with a clutch pedal for starting from a standstill and switching between the "low" and "high" ranges. The Automatic Safety Transmission was replaced by the fully-automatic Hydra-Matic for the 1940 model year. The 1938–1939 Buick Special was available with another Self-Shifter 4-speed semi-automatic transmission, which used a manual clutch for starting from standstill and an automated clutch for gear changes. The 1941 Chrysler M4 Vacamatic transmission was a two-speed manual transmission with an integral underdrive unit, a traditional manual clutch, and a fluid coupling between the engine and the clutch. The two-speed transmission had "high" and "low" ranges, and the clutch was used when the driver wanted to switch between ranges. For normal driving, the driver would press the clutch, select the High range, and then release the clutch. Once the accelerator was pressed, the fluid coupling would engage and the car would begin moving forward, with the underdrive unit engaged to provide a lower gear ratio. At between , the driver would lift off the accelerator and the underdrive unit would disengage. The Vacamatic was replaced by a similar M6 Presto-Matic transmission for the 1946 model year. Similar designs were used for the 1941–1950 Hudson Drive-Master and the ill-fated 1942 Lincoln Liquimatic. Both of these combined a 3-speed manual transmission with automated shifting between the 2nd and 3rd gears, instead of the Vacamatic's "underdrive" unit. The Packard Electro-Matic, introduced in the 1941 Packard Clipper and Packard 180, was an early clutchless manual transmission that used a traditional friction clutch with automatic vacuum operation, which was controlled by the position of the accelerator. 1950s–1960s The automotive products manumatic system, available on the 1953 Ford Anglia 100E, was a vacuum-powered automatic clutch system that was actuated by a switch that was triggered whenever the gear stick was moved. The system could control the throttle cable (to keep the engine at the required RPM for the gear change) and vary the rate of clutch engagement. The successive Newtondrive system, available on the 1957–1958 Ford Anglia, also had a provision