TIL/T&P Masterclass by MSc student Liselotte Kroon about her graduation project on step theory and on litereature review.

1. Validation of the
Step Theory
Witteveen+Bos E.C.M. Kroon
Rijkswaterstaat Master Thesis TIL
TU Delft
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2. Index
n Introduction to the Step Theory
n Literature Study
n Methods
n Driving simulator Study
n The challange of a literature study
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3. INTRODUCTION TO THE STEP
THEORY
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4. Step Theory
n Design speed of successive
road elements should Q1
decrease gradually Q2
120 km/h - 100km/h - 80km/h - 50 km/h
n Goal: facilitate a safe transition
in operational speed, by road
design only
Figuur 1, Haarlemmermeeraansluiting
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5. Step Theory in practice
n Speed Q1 is multiple steps lower
¨ Krappe bocht door beperkt ruimtebeslag is geaccepteerd. Extra
aandacht voor compenserende maatregelen
n Speed between Q1 en Q2 differs multiple steps
n Speed of Q2 does not connect with the underling road
network
n Q1 en Q2 are separated by a short road section, by
which operational speeds at Q2 become too high
n It is unclear whether the deceleration lane can be seen
as a full step
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6. Main goal
n Validation of the Step Theory
To which extend does the step theory contribute to traffic safety at
ramps and F-F connectors on Dutch motorways?
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7. Subquestions
n What is the underlying basis of the step theory and is there literary
support for it?
n Is there a difference in speed profiles for the degree in which the
step theory is applied?
n Is there a difference in traffic safety for the degree in which the
step theory is applied?
n Is there a difference found between road types in relation to the
degree in which the step theory is applied, measured in speed and
crash rate?
n Is there a difference found between road configurations in relation
to the degree in which the step theory is applied, measured in speed
and crash rate?
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8. Research setup
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9. LITERATURE STUDY
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10. Subquestions
n What is the underlying basis of the step theory and is
there literary support for it?
n Which independent factors are of influence on
operational speeds and traffic safety in motorway curves
as well?
n Which road configurations are of interest for this study?
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11. Conclusies [1]
n Hardly any studies towards deceleration behaviour at
motorways
n Consistency theories on step size exist, though there is
no hard validation
n Consistency indicators, like:
¨ Variability in speed Crash rate
¨ Workload, hart rate variability Road position
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12. Conclusies [2]
n Factors to take into account when analysing curves, like:
¨ Curve length
¨ Curve-tangent-curve
¨ Road signs
n Deceleration behaviour on deceleration lanes is likely to
be dependent on the first curve radius
n No literature on differences between connector roads
and ramps
n Configurations
¨ No curve-tangent-curve
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13. METHODE
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14. General setup
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15. Variables
n Stepsize
n Configuration
n Road type
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16. Indicators crashstudy
n Crashes
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17. Indicators Driving simulator [1]
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18. Indicators Driving simulator [2]
n Smoothness
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19. Indicators Driving simulator [3]
n Calculating smoothness
¨ Standerdize over time – absolute difference over time
step – summation to obtain one value
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20. DRIVING SIMULATOR STUDY
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21. Limitations driving simulator
n No hights
¨ No interchange
n No superelevation
n Difference between ramp and connector
road difficult to simulate
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22. Setup
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23. Map
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24. Population
n 45 participants n 3 became motion sick
n 71% man vs. 29% n 4 other dropouts
woman
Age
distribution Distribution
of
driving
experience
16 14
15
14 12
Number
of
participants
[#]
Number
of
participants
[#]
13
12 10
11
10
9 8
8
7 6
6
5 4
4
3
2 2
1
0 0
<25 26-­‐30 31-­‐35 36-­‐40 41-­‐45 46-­‐50 51-­‐55 56-­‐60 61-­‐65 0-­‐5 6-­‐10 11-­‐15 16-­‐20 21-­‐25 26-­‐30 31-­‐35 36-­‐40 41-­‐45
Age
of
participants
[years] Possession
of
driving
license
[years]
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25. Results [1]
n Speed n Lateral position
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26. Results [2]
n Steering angle n Lateral speed
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27. Results [3]
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28. THE CHALLENGE OF A
LITERATURE STUDY
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29. Where to start?
n Quickly gain a broad perspective on your
topic
n Set clear goals
n Structure your literature study and think of
how to present your output
n Reassess halfway!
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30. For what purpose?
Determining
n Variables
n Indicators
n Scope
n Methods
n Oppertunities
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31. Assess literature
n Method used in paper
n Population
n Experimental conditions
n Significance
n Be critical!
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32. Perform your literature review properly and
you will be one step ahead of your
committee
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33. QUESTIONS
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