The lane configuration with lane volumes in vehicles per hour of a four-arm signalized intersection is shown in the figure. There are only two phases: the first phase is for the East-West and the West-East through movements, and the second phase is for the North-South and South-North through movements. There are no turning movements. Assume that the saturation flow is 1800 vehicles per hour per lane for each lane and the total lost time for the first and the second phases together is 9 seconds.

The optimum cycle length (in second), as per the Webster's method, is __________. (round off to the nearest integer).

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)