Whenever a motor vehicle is being operated on a roadway or shoulder adjacent thereto during the times specified in Section 438.02, the driver shall use a distribution of light, or composite beam, directed high enough and of sufficient intensity to reveal persons, vehicles and substantial objects at a safe distance in advance of the vehicle, except that upon approaching an oncoming vehicle, the lights or beam shall be so aimed that the glaring rays are not projected into the eyes of the oncoming driver.