Question

Traffic engineers study how long the yellow light for a traffic signal should be. For one intersection, the number of seconds n required for a yellow light is related to the average approach speed v, in feet per second, by

n=1+v/30+100/v
Given, the approach speed is 80 feet per second (about 55 miles per hour), how long should the yellow light be?

Answer 1

To determine the duration of the yellow light for a given speed, use the formula n = 1 + v/30 + 100/v. For an approach speed of 80 feet per second, the yellow light should last approximately 4.92 seconds.

Step-by-step explanation:

You've asked how long the yellow light should be if the approach speed is 80 feet per second. To find the time n that the yellow light should last, we will use the following equation given for traffic engineering considerations: n = 1 + v/30 + 100/v, where v is the approach speed in feet per second. Let's plug in the given value of v = 80 feet per second into the equation.

n = 1 + 80/30 + 100/80
= 1 + 2.67 + 1.25
= 4.92 seconds

So the yellow light at this intersection should last for approximately 4.92 seconds to accommodate the average approach speed of the vehicles.