Final answer:
Prima facie speed limits are the default legal speed limits for roads under certain conditions, but conviction requires proving the driving speed was unsafe.
Step-by-step explanation:
Prima facie speed limits are the default speed limits set by law for specific types of roads and conditions. For example, many suburban roads have a prima facie speed limit of 25 miles per hour, while on open highways it might be 55 or 65 miles per hour. However, these are not absolute limits—they are subject to other conditions on the road, such as traffic, weather, and visibility. Law enforcement may allow a small cushion above the limit, but exceeding the limit by much can lead to a speeding ticket.
If a driver goes faster than the prima facie limit, they can be ticketed for speeding. But, to be convicted, it must be proven that the speed was unsafe for the conditions, even if it was under the posted de jure speed limit. Drivers often travel slightly above the prima facie limit because law enforcement typically allows a cushion, recognizing the variance in speedometer accuracy and to focus on more serious violations. It's important to note that exceeding this unwritten de facto limit significantly increases the likelihood of being pulled over.