The already fuel efficient Smart fortwo will soon become even more stingy with the petrol when start-stop technology is employed fleet-wide beginning in October. The start-stop technology, which is called "micro hybrid" by Smart, works by cutting off the engine during braking when the vehicle speed drops below five mph. According to Smart, the engine restarts immediately when the brake is released and the technology will result in a fuel savings of 8 percent, bringing consumption in the US EPA cycle to about 44 mpg on the highway and 36 mpg in the city. CO2 emissions will also be reduced by 9g/km, now netting 103g/km. The technology will also be available on the CDI Smart when it hits production next year, but as of right now, the diesel fortwo isn't coming Stateside.