For a traffic stream, V is the space mean speed, k is the density, q is the flow. V_f is the free flow speed, and k_f is the jam density. Assume that the speed decreases linearly with density.

Which of the following relations is/are correct?

Consider the four points P, Q, R and S shown in the Greenshields fundamental speed-flow diagram. Denote their corresponding traffic densities by k_P, k_Q, k_R and k_S, respectively. The correct order of these densities is :

A two-phase signalized intersection is designed with a cycle time of 100 s. The amber and red times for each phase are 4 s and 50 s, respectively. If the total lost time per phase due to start-up and clearance is 2 s, the effective green time of each phase is _________ s. (in integer)

At a traffic intersection, cars and buses arrive randomly according to independent Poisson processes at an average rate of 4 vehicles per hour and 2 vehicles per hour, respectively. The probability of observing at least 2 vehicles in 30 minutes is __________. (round off to two decimal places)