 While operating modes are switched automatically the Volt allows the driver to choose from three drive modes : normal , sport and mountain . The mountain mode , which is expected to be required only under unusual power demand conditions , increases minimum battery state of charge ( SOC ) to around 45 % , thus maintaining performance on steep and long grades . The driver will hear more engine noise due to the higher rate of power generation required to maintain this mode . The sport mode causes the engine to rev higher , and the response to the throttle pedal is quicker . The Ampera has an additional option , the " City Mode " or " battery hold " , allowing the driver to save the energy currently stored in the battery for use when traveling in urban areas or restricted zones . The 2013 model year Volt includes a " Hold " option to provide the same choice . 
