Sections of this interstate have speed limits of 65mph. A construction site is located on this interstate near Boise, ID. In the construction site, the speed limit is reduced to 20 mph. A warning sign reading "WORK ZONE: 20 MPH SPEED ZONE" is required to be put before the start of the construction site so as to allow drivers to decelerate before entering the work zone. The sign is located 20 ft. to the side of the road, the deceleration rate of the vehicle is 11 ft./sec2 (recommended maximum deceleration rate by AASHTO) and the driver is assumed to have 20/40 vision. You may assume a perception time of 1 sec, an interpretation rate of 3 words/sec, and a decision time of 0.5 sec. Assuming the road is level answer the following questions.

a. What should be the minimum distance away from the warning sign from where the driver is able to read the warning? (Assuming 10 degree cone of vision and the vehicle is moving on the side of the road i. e. lateral distance between car and warning sign is 20 ft.)

b. Determine the total time taken by driver before he applies brakes. Also, determine the distance travelled during perception, interpretation, and reaction.

c. Assuming that the driver reacts only once he is out of 10 degree cone of vision, calculate the minimum distance away from the start of the construction site where a warning sign must be located to allow drivers to decelerate before entering the work zone.

d. Determine the minimum size of the text on the sign.