# Fundamentals of Transportation/Shockwaves/Additional Problems

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## §Additional Questions

1. What example or explanation can be given for shockwaves on freeways?
2. Explain the 4 phases of traffic diagram and why each has the slope it has.
3. How do microscopic and macroscopic models of traffic flow differ?
4. Why does flow decrease in phase 3 of the traffic phase diagram?
5. What types of events can create rolling roadblocks?
6. How is speed calculated from a flow v. density diagram?
7. What is a shockwave and how do you compute its speed?
8. Can service rate decrease with increasing congestion?
9. What factors affect the wave speed?
10. What does the slope of the shockwave represent in the graph?
11. Is it possible to increase the density of the queue and still have the shockwave going downstream? What would be a an example of this?
12. Why is the bottleneck QK curve projected on the mainroad QB curve to find the speed?
13. What is Greenshields model, does it accurately predict traffic flow?
14. What is the phase in traffic flow, after density is at its max, called?
15. What happens to speed when the density increases?
16. What does the slope represent in a traffic phase diagram
17. Give an example of density rising and speed dropping
18. What is $v_w$ ?
19. What does it mean when the flow rate begins to decrease in the traffic phase diagram?
20. During the bottleneck phase, what happens to flow as density increases? (flow remains constant)
21. How can you tell if the queue grows with or against traffic?
22. Does the bottleneck always slow traffic?
23. How can traffic avoid the bottleneck?
24. How do incidents and rolling roadblocks affect shockwaves differently?
25. How do speed, density, and flow change during the peak hour
26. List six examples where gaps are important.