Video sequences of road and traffic scenes are now used for various purposes. The framework of this research on the metric potential of single uncalibrated images is road mapping and studies of the traffic character of freeways. In the first case, an approach has been developed to extract lane width in straight road segments exploiting sequences from a forward looking camera. Apart from an initial reference width, necessary for calibrating camera height, no intrinsic or extrinsic calibration is required if frontal image acquisition is assumed. This approach, making use of the vanishing point of the road, gave an accuracy better than 5 cm in lane width. The second technique regards the measurement of vehicle speed, given the time interval between frames of a stationary camera tilted downwards. Here, too, the vanishing point in the direction of the road is used, with the vanishing point of the orthogonal direction assumed at infinity. Given one known ground distance along the road axis, the projective distortion of the ground plane is removed, allowing an affine rectification and, thus, 1D measurement in the correctly scaled road direction. This approach, evaluated against rigorous 2D-2Dprojective transformation and GPS measurements, has given a satisfactory estimated accuracy in vehicle speed of about 3 km/h.