Looking to boost its cars' average mileage by 30 percent in seven years, Mazda has developed an advanced stop-and-go system, diesel engine and other technologies, according to Reuters.

Mazda's new stop-and-go feature increases fuel efficiency by about 10 percent in urban areas, where cars stop frequently at traffic lights.

The system controls the position of the pistons when the engine stops automatically during idling. Mazda said this enables a quick and quiet start by directly injecting fuel into the cylinder in the optimal position. Mazda added that the system is the first in the world to do this.

The technology enables a restart of the engine in 0.35 second, or about half the time that existing systems take, Mazda said. It will be introduced in cars in Japan and Europe next year.

To reach its fuel economy goal for 2015, Mazda will also start replacing resin-based parts on its new models, beginning in a few years, with lighter material to reduce vehicle weight.

Announcing the new plastic molding technology on Sept. 9, Mazda said the technique would slash consumption of plastic resins by 20 to 30 percent, also helping to cut costs, according to Reuters.