Given the word problem, we can deduce the following information:
1. The formula V=2.5r can be used to estimate the maximum safe velocity,v, in miles per hour, at which a car can travel if it is driven along a curved radius of curvature r in feet.
2. The radius of curvature is 280 feet.
To determine the maximum safe speed, we use the given formula as shown below:

where:
V= Maximum safe velocity in miles per hour
r=radius of curvature = 280 feet
We plug in what we know:

Therefore, the maximum safe speed is 700 miles per hour.