Aggressive driving in city traffic saves very little time but greatly increases fuel consumption and emissions. It is also hard on the engine and brakes. A European test showed that aggressive driving – "jackrabbit" starts from traffic lights and hard braking – reduced travel time by only 4 % (the equivalent of 2½ minutes out of a 60–minute trip). However, fuel consumption increased by 37 %, and some toxic emissions were more than five times higher. The safer, more fuel-efficient option is to accelerate smoothly and maintain a steady speed