CIVL2700/9700 TRANSPORT SYSTEMS
ASSIGNMENT 3
Due: Wednesday 15 May 2024
• This individual assignment is worth 10% of the total mark. The report should include your working process and final answers of problems.
• You must submit the report electronically on Canvas.
ACADEMIC HONESTY
• Students are always encouraged to help each other with studying, however copying solutions from anyone, where you have little or no academic input is not acceptable. Any form. of copying is not acceptable.
Problem 1
a. A pre-timed four-phase signal has critical lane group flow rates for the first three phases of 260, 280, and 310 [veh/h] (saturation flow rates are 2000 [veh/h/ln] for all phases). The lost time is known to be 5 seconds for each phase. If an optimal cycle length of 90 seconds is being used, determine the effective green time for each of the phases. (5%)
b. The minimum cycle length for an intersection is determined to be 95 seconds. The critical lane group flow ratios were calculated as 0.235, 0.25, 0.17, and 0.125, respectively. Assuming 5 seconds lost per phase, determine which xc was used. (5%)
c. An intersection approach has a saturation flow of 1500 veh/h, and vehicles arrive at a rate of 800 veh/h. The approach is controlled by a pre-timed traffic signal with a cycle length of 60 seconds. Local standards dictate the queues must dissipate at least 10 seconds before the end of the effective green time. Determine the maximum length of the effective red that will satisfy these standards. (5%)
Problem 2 (40%)
Develop a signal design and timing for the intersection shown in the figure below. In each case accommodate both vehicular and pedestrian movements. In general, use the following values for the problem: pedestrian walking speed = 1 [m/s], vehicle deceleration = 3 [m/s2], driver reaction time = 1.5 [s], length of vehicle = 6 [m], and level grade = 0. Assume this occurs in Australia, and justify the number of phases you decide to consider.
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Speed limit = 50 [km/h]
Pedestrian = 15 per each crosswalk
Crosswalk widths = 3 [m] Lane width = 4 [m]
Saturation flow = 1800 [veh/h/lane]
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Problem 3 (45%)
a. Assume a bus line with N stops, where distance between stops is S. Free flow speed of the bus is v, with acceleration and deceleration, a. pb passengers per stop are boarding and alighting and time needed for a passenger to board or alight is T seconds. What is the average speed of a bus? (10%)
b. Following on part (a), assume the origin of passengers are spread uniformly along the bus route. The destination of all passengers is the last stop. The walking speed of passengers is u. Determine the average travel time (walking + in-vehicle time) of passengers, and show that if N is large, you can approximate this quantity by
(1)
(15%)
c. Assume Eq. (1) holds. Consider now that you can decide on S, where you approximate N=L/S (L is the length of the route). Find the value of S that minimises the travelling time of the passengers. (10%)
d. In the same setting as (c), assume that some passengers do not goto the terminal but alight before. Explain if your answer from (c) would increase or decrease and why. (10%)