Suppose vehicles are moving at 72 kph (kilometers per hour). Each car carries an average of 1.5 people, and all are carefully keeping a 2- second following distance (getting no closer than the distance a car travels in 2 seconds) on a three-lane highway.
a. How far between vehicles?
b. How many vehicles per kilometer?
c. How many people will pass a given point in an hour?
d. If commuter number oscillates between this maximum (at 8:00 A.M.) and a minimum that is one third as large (at 8:00 P.M.) on a 24-hour cycle, give a formula for the number of people passing the given point as a function of time of day.