48370 Roads and Transport Engineering at UTS Assessment Answer

Question 1

Five test vehicles are travelling around the world famous Autodromo Nazionale Monza looped race track in Italy (10km per lap). As this is a vehicle testing session and not a race, the vehicles maintain the following constant speeds while travelling around the circuit: 80km/h, 90km/h, 100km/h, 110km/h and 120km/h.

a) Imagine you stand at a point on the track and observe the vehicles driving around the track for one hour, how many times will you observe the fastest car? How many times will you observe the slowest car?

ans- 

1. fastest car=120/10=12 times

2. Slowest car=80/10=8 times

b) What is the flow rate you measure across the one hour survey?

ans- 

Flow rate

Flow rate=Number of vehicles passing a point/stated time period

q=n/t

q=5/1 =5 vehicles/hr

c) What is the time mean speed of the observed vehicles?

1. Time Mean Speed

A time mean speed is

ui = speed of an individual vehicle i

N = the number of vehicles passing a point during the selected time period.

Time mean speed=80+90+100+110+120/5=100 km/hr

d) What is the space mean speed of the observed vehicles?

ans- Space Mean Speed

The Space Mean Speed is

=

‘t_i’ is the time for vehicle ‘i’ to cross the distance ‘L’

ti=

L=roadway segment

Space Mean Speed=5/(1/80+1/90+1/100+1/110+120)=5/(0.0125+0.0111+0.01+0.009+0.0083)= 98.23 km/hr

Question 2:

A new model relating Speed and Density (20 marks) A model of the relationship between speed (????????????????) (in kilometres per hour) and density (k) (in vehicles per kilometre) for a particular roadway is characterised as:

ans- 

1. The free flow speed is 60 km/hr

vs =100-0.67k

 is free-flow speed

60=100-0.67k

60-100=-0.67k

-40=-0.67k

k=40/0.67=59.7 vehicles/kilometer (vehicles per km)

1. q=
2. d) =(100-0.67k)

0.67k=100-

k=(100-/0.67=149.25-

q=

q=149.25-)

q=3582 vph

Question 3: Gap Acceptance
Traffic in the southbound direction of a local street stops at a red light for 30 seconds. The yellow and green cycle of the light is 45 seconds. Assume the queue has cleared from the previous cycle and that vehicles can travel during both the green and amber periods of the cycle, the arrival rate is 600 vehicles per hour, and the capacity is 1800 vehicles per hour.

a) Sketch the queuing diagram for one cycle of the traffic signal beginning with the red phase for the approach described in the question. Clearly label the arrivals and departures, the maximum queue length and the maximum time in the queue.

ans- 

b) What is the maximum length of the queue? 

ans- Maximum queue length=300 vehicles

c) What is the maximum time in queue?

ans- Maximum time in queue=30 seconds

d) When will the queue clear and why will it clear at this point in time?

ans- 

The queue will clear after 45 seconds because the yellow and green signal display at this time and the queue will be cleared

Question 4:

Overall Learning Outcomes (10 marks) Briefly describe the difference between transport planning and transport engineering using an example of your choice. Clearly present the role of both a planner and an engineer and explain why both professions are important in the context of Civil Engineering.

Ans- 

A transport has an engineering degree and he performs both design and planning task. While a transportation planner cannot perform the design tasks without an engineer. Engineer focus on technical expertise and specifics that is needed for design. However, planner supervise the whole project. For instance, it is less likely that planner lonely would focus on drainage feasibility or utility of design which are important components for development of site. Similarly, it is less likely that a civil engineer will consider property restrictions and zoning regulations.

Both engineering and planning teams must consult each other during site design and site permitting. It will less conflicts between functions and location of site elements. Transportation planning and engineering is related with people goods movement and people movement through air, water, rail, highways, and information technology.

An engineer handles his projects carefully by proper planning and organizing. A plan of project is helpful to get better the end product quality, better dynamics of team, and well-being of company.

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