Final answer:
The typical highway speed limit is around 60 miles per hour, but this can be reduced in highway work sites, where lower limits are posted for safety. Conversations of kilometers per hour to miles per hour are used to understand speed limit conversions.
Step-by-step explanation:
The highest legal posted speed limit in a designated highway work site can vary depending on the jurisdiction, but the discussions provided suggest a typical highway speed limit around 60 miles per hour. When considering work zones, this limit may be posted lower to ensure safety. For instance, converting speed limits from km/h to mi/h indicates that 100 km/h is approximately 62 mi/h (as 1 mile is roughly 1.609 km). Similarly, 80 km/h would be around 49.7 mi/h. In residential areas, a commonly posted speed limit is 50 km/h, which is equivalent to about 31 mi/h. It's important to adhere to the posted speed limits, especially in work zones, as they are implemented for the safety of both the workers and the drivers.