Final answer:
When parking next to a curb, your car's back wheel must be within 12 inches of it. This regulation helps maintain clear roads and ensure safety. For pedestrian safety, multiple car-lengths of a gap in traffic are recommended for crossing streets, although the exact distance can vary.
Step-by-step explanation:
When parking next to a curb, the back wheel of your car must be within 12 inches (30 centimeters) of the curb. This is a common traffic law in many places, aiming to keep roads clear and prevent obstruction of traffic. It's important to be aware of local parking regulations as they can vary, but typically, a distance of more than 12 inches would be considered too far from the curb and may lead to a ticket or fine. For safety when crossing a street, you should ensure there is a significant gap in traffic, typically multiple car-lengths, to allow enough time to cross safely. This distance cannot be defined in car-lengths specifically as it depends on the road size, traffic conditions, and pedestrian speed.