HONDA engineers designed a new five-speed manual transmission for the Insight to meet design objectives of weight reduction and compact dimensions. Honda claims the shift linkage operates smoothly and requires minimal effort as a result of shortened synchroniser sleeves and a redesigned reverse-gear mechanism. A neutral switch built into the transmission informs the IMA (integrated motor assist) system's idle-stop feature when the driver shifts into neutral. Wherever possible, the petrol engine shuts down to save fuel and minimise emissions.