Timing Plan. You have just received the traffic-timing data and distance data forVineStree...

Timing Plan. You have just received the traffic-timing data and distance data forVineStreet (below). Vine is a main north–south thoroughfare from 12th Street to Main Streetthatcarries much traffic. Your office is getting many angry letters from motorists, and the newsmediacall it the “Mile of Creeping Vine.” Most complaints come from those who travel at the peak periods. They say that too many signal cycles are needed to travel along this street, even whentraffic is light. They say the speed limit is a myth. It should be posted as 15 mph.

• The timing data are in seconds.

• The cycle of each signal is fixed.

• The distance between the centers of adjacent intersections with signals is given in feet.

• The intersections are 60 feet wide.

Both 12th Street and Main Street are major through fares and their 30 second green phases at Vine are based on traffic along those routes, which flows quite well. Each light has a 4-seeond yellow that subtracts from the green. The speed limit along Vine is posted at 40 mph.

(a) Construct a lime-space diagram for the present system.

(b) What speeds can the present light settings accommodate northbound and southbound?

(c) All of the signals from 1st Street to 9th Street can be reset with green as long as 45 seconds and red as short as 10 seconds. Adjusting the offsets so that the speed limit is not exceeded, from the end of green when entering Vine southbound at Main to the beginning of

		Gon	Ron	Gon	Ron	Gon	Ron	Gon	Ron	Gon
	Main street	0	30	60	90	120	150	180	210	240
880 ft
	1st Street	0	30	40	70	80	110	120	150	160
550 ft
	2nd Street	-20	-5	20	35	60	75	100	115	140
550 ft
	3rd Street	0	25	40	65	80	105	120	145	160
550 ft
	4th Street	-15	0	25	40	65	80	105	120	145
1100 ft
	6th Street	-5	25	35	65	75	105	115	145	155
1100 ft
	8th Street	0	25	40	65	80	105	120	145	160
550 ft
	9th Street	-15	0	25	40	65	80	105	120	145
1650 ft
	12th Street	-10	20	50	80	110	140	170	200	230

green at 12th Street. Set the signals first to achieve green wave flow in this direction. Set them first for the southbound trip (Main to 12th).Then check the flow for northbound traffic. Because the signals we presently have cannot be changed for time of day, what compromises will you make?

(d) What speed will your final solution permit you to achieve in each direction?