What does a rectangular sign with 'DO NOT PASS' signify for drivers?

A rectangular sign displaying 'DO NOT PASS' indicates that passing other vehicles is prohibited in that particular area. This sign is commonly found on roads where visibility may be limited, such as hills or curves, where passing could create dangerous situations for both the driver and others on the road. It serves as a critical warning to ensure safety by preventing overtaking in potentially hazardous zones.

Understanding the implications of this sign helps drivers to recognize that adhering to the warning can significantly reduce the risk of accidents. The other options reflect misunderstandings of driving regulations: passing is not encouraged in this context, there is typically a speed limit regardless of passing zones, and passing on the left is not allowed at locations marked by this sign.