The speed-density relation on a one-way, single lane road is shown in the figure, where speed $u$ is in km/hour and density $k$ is in vehicles/km. The maximum flow (in vehicles/hour) on this road is

The figure presents the time-space diagram for when the traffic on a highway is suddenly stopped for a certain time and then released. Which of the following statements are true?

A plot of speed-density relationship (linear) of two roads (Road A and Road B) is shown in the figure.

If the capacity of Road A is CA and the capacity of Road B is CB, what is $\rm \frac{ C_A}{C_B }$?
Assuming that traffic on a highway obeys the Greenshields model, the speed of a shockwave between two traffic streams (P) and (Q) as shown in the schematic is __________ kmph. (in integer)