Final answer:
Maintaining sight distance in city driving requires understanding depth perception and accommodation of your eyes. You should ensure you have enough crossing distance before a car reaches you, based on its speed and distance.
Step-by-step explanation:
Maintaining a good sight distance while driving in city areas is crucial for safety. To do this, be aware of the capabilities and limits of your depth perception and how it affects your ability to judge distances. For example, understanding that the distance between two just-resolvable points, such as a car's headlights, helps gauge when it's safe to cross the street. In towns and cities with a speed limit of 60 km/h, consider the length and width of an average car when estimating the required time to cross safely.
Your eyes can resolve two objects as separate when the angular separation between them is large enough. This is why depth perception diminishes for objects more than a few tens of meters away. When assessing if it's safe to cross a road, consider that you must be able to walk at least 4 meters before a car reaches you, which means the car should be several car-lengths away. Your eyes perform accommodation, adjusting the lens's focal length for clear vision at various distances.