Also calledidle-stop orsmart-start

These systems automatically turn the engine off when the vehicle comes to a stop and restart it instantaneously when the the brake is released or the accelerator is pressed. This reduces fuel wasted during idling.

Also calledintegrated starter generator (ISG),belted alternator starter (BAS),electronic assist (eAssist)

These systems use Stop-Start technologies to reduce idling. Regenerative braking is also used to convert mechanical energy lost in braking into electricity. The electricity is stored in a battery and used to power the automatic starter and to aid in acceleration for very short distances.

Full hybrids use Stop-Start systems and regenerative braking. Compared to mild hybrids, they use a larger battery and a more powerful electric motor. This allows the electric motor to assist the engine or propel the vehicle by itself at lower speeds. They can also travel much farther using electricity than mild hybrids.

It takes less energy to propel a lighter vehicle than a heavier one. Manufacturers are reducing weight by designing vehicles to use less material, using lighter weight materials, and downsizing the powertrain. Weight can be reduced without reducing vehicle size, safety, or riding comfort.

When rolling, a tire is continually deformed by the load of the vehicle on it. This causes energy loss. Manufacturer changes to tire shape, materials, and tread design can reduce rolling resistance and improve fuel economy.