No person shall drive a vehicle at a speed greater or less than is reasonable or prudent under the conditions then existing, taking into consideration, among other things, the condition of the vehicle, the traffic, roadway surface or width, the amount of light or darkness, the presence of pedestrians in or near the roadways, and the obstruction of view. No person shall drive any vehicle at a speed greater than will permit him to bring it to a stop within the assured clear distance ahead. (1990 Code § 15-403)