Samenvatting
Stopping and passing sight distance criteria for the vertical curvature of roads at hillcrests are compared. Considered are (1) the visibility of an object coming into view being a function of the area of the object, the contrast between the object and its background, and the light level; (2) for stopping sight distances the effective driver eye height at night is the headlamp height, and (3) visibility in the meeting-vehicle situation at night time and at hillcrests can be considerably less than the minimum stopping sight distances.