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Final Exam

• Tuesday, December 9• 2:30 – 4:20 pm • 121 Raitt Hall

• Open book• Open note

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Exam Questions

• Group evaluation• Short answer (2 points, 20 points total)• Short calculations (5 points, 20 points total)• Calculations (20-30 points, 160 points total)

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Course Material Covered

• Vehicle Dynamics• Geometric Design• Pavement Design• Traffic Flow Theory• Queueing Theory• Level of Service• Signalized Intersections• Transportation Planning

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Suggestions for Preparation

• Review each lecture and identify the main points and formulas. Write these on summary notes.

• For each lecture, write an question. Do this in a group, and share questions.

• Solve these questions from scratch, do not just review solutions.

• Review homework and in class examples. Do the problem yourself.

• Make a list of the tables in the text, their title, and the page number. Include a note of what it is used for.

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Vehicle Dynamics

• Calculate resistive forces and relate to vehicle speed/acceleration

• Calculate engine generated tractive effort and maximum tractive effort

• Calculate engine speed• Calculate braking force• Calculate stopping distance

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Geometric Design

• Stationing• Vertical alignment

– What is basic form?– What are governing constraints?– Standard assumptions (driver height)

• Horizontal alignment– What is basic form?– What are governing constraints?– Standard assumptions– Definition of Ms, Rv, R

• Go through the variety of equations and identify use for each.

• Meaning and applications for K

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Geometric Design

• Check a design speed allows for constraints to be met

• Provide one or two aspects of a design• Short question: a geometric relationship

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Pavement Design

• Define pavement, purpose• Describe pavement types and qualities• Define ESAL• Calculate ESALs

– Account for future growth

• Design pavement

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Traffic Flow Theory

• What are functional forms and relationships?

• Use equations to solve for missing variable

• Calculate SMS, TMS• Convert from spacing to headway• Identify congested or uncongested flow.

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Queueing Theory

• Understand arrival, departure, service framework and relationships

• Convert between rates and times• What does a poisson arrival mean, and

imply for inter-arrival times?• What is queue discipline?• Use time versus cumulative number of

items diagram

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Poisson Distribution

• Good for modeling random events• Count distribution

– Uses discrete values– Different than a continuous distribution

!n

etnP

tn

P(n) = probability of exactly n vehicles arriving over time t

n = number of vehicles arriving over time t

λ = average arrival rate

t = duration of time over which vehicles are counted

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More queueing theory

• How to determine average queue length, wait time, number in system for M/D/1, M/M/1, and M/M/N queueing system.

• What is the source of delay if average arrivals are less than average departures?

• How to determine total delay for D/D/1 system?

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Level of Service

• Calculate level of service– Freeway, multi-lane highway– Know how to find and use tables in text

• Identify flow to achieve certain LOS

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ITS

• How to calculate speed from loop detector data– Occupancy– On time

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Signalized Intersections

• Know definitions/framework so that you can interpret questions.– What are critical lane groups and why are these

important?

• Be able to use a queueing diagram to analyze signal cycles.– Beginning and ending queues– What assumptions is this relevant for?

• Be able to use equations to analyze signal cycles.– What assumptions is this relevant for?

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D/D/1 Signal Analysis – Numerical

• Time to queue dissipation after the start of effective green

• Proportion of the cycle with a queue

• Proportion of vehicles stopped

0.1

10

rt

c

trPq

0

qs P

c

tr

gr

trP

00

c

t

c

t

gr

trPs

000

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Signalized Intersections

• Calculate signal LOS– Uniform delay– Incremental delay– Initial queue delay

• Calculate minimum cycle length• Calculate optimal cycle length• Estimate green time• Check pedestrian crossing time

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Transportation Planning

• What is the purpose of transportation planning?

• What are the four modeling steps to the transportation planning process?

• What question do each of these steps try to answer?

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Trip Generation

• What does the Poisson assumption mean in this case?

• How to estimate the number of trips• How to estimate the probability of some

number of trips• What is the form of the distribution of

inter-trip times?

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Example Graph

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Trips in a Day

Pro

bab

ility

of

Occ

ura

nce

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Mode Choice

• What question does a mode choice model answer?

• What do the parameters mean?• What form of model did we consider?• How to use the model to estimate mode

– Calculate probability of mode choice– Estimate mode choice for a population

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A Mode Choice Model

• Logit Model

• Final form

mkn

kmnmnmk zV

s

U

U

mk sk

mk

e

eP

Specifiable part Unspecifiable part

n

kmnmnmk zU

s = all available alternativesm = alternative being consideredn = traveler characteristick = traveler

Look at HW 9 to interpret values

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Route Choice

• What is a HPF?• What relationship does the HPF capture?• What are the limitations of the HPF?• What is UE solution and how to calculate• What is SO solution and how to calculate• How do the UE and SO solution compare?

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Other quantitative skills

• How to find optimal solution• How to solve quadratic equation• How to integrate/differentiate