Design a traffic light controller at the intersection of a a heavily traveled highway and a local road. the controller is described by the following specification.

(a) the signal lights at the highway are labeled {ryg}, for red, yellow, and green.
(b) the signal lights at the road are similarly labeled {r y g}, designating the respective colors.
(c) a sensor v is placed at the intersection which senses the presence (v=1) or absence (v=0) of a vehicle on the road.
(d) initial state: initially a g/r signal combination is applied (green on highway / red on the road).
(e) normal mode: if there are no vehicles on the road, the g/r signal combination is maintained.
(f) emergency mode: if a vehicle is sensed on the road, the lights should cycle from g/r to y/r to r/g to allow the vehicle to cross the intersection. each transition takes 5 seconds.
(g) the state r/g is maintained as long as vehicles are present at the road.

draw a block diagram, clearly indicating the combinational portion of the design, the d flipflops, all interconnections, and all inputs and outputs.