99 Under Nath

Question 2 If the model In us= ln uf - k/kj is applicable to depict the correlation between speed (mi/h) and density (veh/mi) on a highway segment, and employing regression analysis provides the model constants Y = A + BX (where Y = In u, X = k) as A = 3.9 and B = -0.018, then calculate the: Jam density in veh/km. Express answer into two decimal places. Do not type the unit. veh/km.

Use linear regression to fit the highway speed/density data shown here to the Greenshields model, and use it to determine: a. The mean free flow speed b. The jam density The capacity The speed at max flow R² of this data

The traffic demand for a six-lane urban arterial road (three lanes per direction) is given in the table below. The relationship between flow and density for this road follows GreenShiled's model, with a free flow speed of 105 km/h and a jam density of 92 veh/km/lane. Two of the three lanes of the EB direction were closed at 5:00 AM for maintenance. The two lanes were re-opened at 8:00 AM, allowing the traffic to be released at capacity conditions. a) What is the maximum length of the queue upstream of the bottleneck? b) At what time the queue upstream of the bottleneck will be fully dissipated? c) What is the furthest point upstream of the bottleneck that will be impacted by the lane closure? d) Draw the shock wave diagram showing shock wave speeds, critical times, and distances. Time 5:00 6:00 AM 6:00 7:00 AM 7:00 8:00 AM 8:00 9:00 AM 9:00 10:00 AM 10:00 11:00 AM Demand (vph) 2000 4000 6400 6000 3600 3000

QUESTION 10 One lane of a uniform section of highway has an optimum density of 70 vehicles per mile and an optimum speed of 35 miles per hour. Calculate the free flow speed (mph).

The data shown below were obtained by time-lapse photography on a highway. Use regression analysis to fit these data to the Greenshields model and determine the following. Speed (mi/h) Density (veh/mi) 84 16.2 24.7 69 33.3 54 39.7 40 52.0 19 55.1 14 (a) the mean free speed (in mi/h) mi/h (b) the jam density (in veh/mi) veh/mi (c) the capacity (in veh/h) veh/h (d) the speed at maximum flow (in mi/h) mi/h

Assuming that the expression: u = ue i, can be used to describe the speed-density relationship of a highway, determine the capacity of the highway from the data below using regression analysis. k (veh/mi) u, (mi/h) 43 50 38.4 33.8 53.2 42.3 31 Under what flow conditions is the above model valid?

Make a cumulative vehicle diagram and queue accumulation polygon based on the following field data collected from an approach at a signalized intersection, namely: 1. Cycle length = 72 seconds 2. Red interval = 30 seconds 3. Green interval = 42 seconds 4. Vehicle arival flow = 900 vehicles/hour %3D %3D 5. Saturation flow rate = 1800 vehicles/hour 6. Vehicle departures every 2 seconds

4. The relation of the density (d) along a roadway to vehicle speed (s: km/h) is given as d = 50- s/2 Determine the flow (q)-speed (s) and flow (q)-density (d) relationships and draw the variations of density-speed, flow-speed and flow-density on. Show the maximum and minimum points on these graphs

Q4 / The data from moving observer methods as shown in the table. Column 1 gives the sample number, column 2 gives the number of vehicles moving against the stream, column 3 gives the number of vehicles that had overtaken the test vehicle, and last column gives the number of vehicles overtaken by the test vehicle. Find the flowrate, density and mean speed. Also, plot the fundamental diagrams of traffic flow. 2 3 4 No. Sample 1 107 10 74 113 25 41 3 30 15 4 79 18 9.