No person shall on a public road -
(a) drive a vehicle; or
(b) occupy the driver’s seat of a motor vehicle the engine of which is running,
while the concentration of alcohol in any specimen of breath exhaled by such person is not less than 0,24
milligrams per 1 000 millilitres, or in the case of a professional driver referred to in section 32, not less than 0,10 milligrams per 1000 millilitres.