Final answer:
U-turns are illegal near the top of a hill or on curves where visibility is restricted, often within 500 feet, to ensure the safety of all road users.
Step-by-step explanation:
The question pertains to traffic laws regarding the legality of U-turns under certain conditions. U-turns are generally illegal near the top of a hill or on curves where drivers of other vehicles cannot see you within a specific distance. Although this specific distance can vary by jurisdiction, a common distance is often around 500 feet. It is crucial for drivers to have a clear view of oncoming traffic to execute a U-turn safely. Performing a U-turn where visibility is restricted not only violates traffic laws but also significantly increases the risk of collisions.