Final answer:
A de jure speed limit sets the legal maximum or minimum speed for a roadway, while the de facto speed limit captures the speed enforcement threshold. Ideal speed is the safest speed for maneuvering curves, relevant in physics.
Step-by-step explanation:
A de jure speed limit is the maximum or minimum speed that a vehicle may be driven on a particular roadway, as indicated by road signage. For example, the de jure speed limit might be thirty-five miles per hour, which is legally enforceable. In contrast, a de facto speed limit refers to the speed at which law enforcement is likely to initiate a traffic stop, which may be slightly higher than the posted limit due to enforcement tolerance or speedometer inaccuracies.
Concepts like ideal speed also come into play, defined as the maximum safe speed at which a vehicle can turn on a curve without relying on the friction between the tire and the road. This concept is pertinent to physics as it relates to the force and motion of the vehicle.