Final answer:
The maximum daytime speed limit for passenger cars on highways in the United States is around 100 km/h or 62 mi/h, with the speed limit historically being set at 55 mi/h during the 1970s oil crisis.
Step-by-step explanation:
The maximum daytime speed limit for passenger cars on a highway numbered by this state or the United States varies, but for the purpose of this question, we will examine typical highway speed limits. The speed limit on some interstate highways is roughly 100 km/h, which is equivalent to about 62 miles per hour (mi/h) since 1.0 mile is approximately 1.609 kilometers.
Furthermore, when considering conversion to meters per second, 100 km/h translates to 27.8 meters per second (m/s), providing a useful basis for comparison with posted speed limits.
During the 1970s oil crisis in the United States, to conserve fuel, the maximum speeds on highways were set at about 90 km/h, which is 55 mi/h. However, the typical highway speed limit now is higher, around 60 mi/h, which is 27 m/s or 96 km/h, giving us a broader context for speed limits on highways.