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THE USE OF THE UCF DRIVING SIMULATOR TO TEST THE CONTRIBUTION OF LARGER SIZE VEHICLES TO REAREND COL

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Title: THE USE OF THE UCF DRIVING SIMULATOR TO TEST THE CONTRIBUTION OF LARGER SIZE VEHICLES TO REAREND COL


1
THE USE OF THE UCF DRIVING SIMULATOR TO TEST THE
CONTRIBUTION OF LARGER SIZE VEHICLES TO REAR-END
COLLISIONS AND RED LIGHT RUNNING ON INTERSECTIONS
Masters Thesis SUMMER TERM 2005
2
KEYWORDS
LTV Light Truck Vehicle e.g. SUV, VAN,
etc. LSV Larger Size Vehicle e.g. S
EMI, SCHOOL BUS,
3
CHAPTER 1 INTRODUCTION
  • 1.1 Problem statement
  • Visibility blockage (vertical or horizontal) at
    intersections is the main concern of our
    research.
  • Horizontal visibility blockage occurs at
    unsignalized intersections where the visibility
    for a passenger car driver driving behind an LTV
    is inhibited to his left and right.
  • Vertical visibility blockage occurs at signalized
    intersections where the vertical visibility ( of
    the traffic light) for a passenger car driver
    driving behind an LSV is inhibited .

4
  • 1.2 Research objectives
  • To determine whether driving behind an LTV
    increases the probability of rear-end collisions
    due to horizontal view blockage.
  • To verify that driving behind an LSV contributes
    to red light running due to vertical view
    blockage at intersections.
  • To verify the ability of adding an additional
    traffic light on the side of the road to solve
    vertical visibility problems.
  • To evaluate drivers behavior model at
    intersections, including speeds, accelerations,
    and decelerations when driving behind LTV and
    LSV.

5
1.3 Literature review
  • 1.3.1 Horizontal visibility blockage literature
    review
  • According to NCSA, in year 2003 rear-end
    collisions accounted for about 1/3 of the 6
    million crashes reported nationwide.
  • Abdel-Aty et al. (2003) stated that the LTVs
    block the visibility of passenger cars drivers
    if they drive behind LTVs.
  • Polk (2001)stated that LTV are becoming more
    common on U.S. highways. For year 2000, Motor
    vehicle registrations show 77.8 million light
    trucks in the U.S., a 63.8 increase from 1990.
    During the same period, there was 1 decease in
    the number of passenger cars (PCs). LTVs now
    present 40 of all registered vehicles
  • Sayer et al. (2000) asserts that passenger cars
    followed LTVs at shorter distance which could
    lead to higher probability of rear-end
    collisions.
  • Acierno (2004) related the mismatch between
    weight, stiffness, and height between LTVs and
    passenger cars to the increase in fatalities
    among passenger car occupants.

6
  • 1.3.2 Vertical visibility blockage literature
    review
  • Retting et al. (2002) reported that red light
    running causes 260,000 crashes every year from
    which 750 are fatal.
  • According to the Federal Highway Administration
    (FHWA), in year 2001 there were 200,000 crashes,
    150,000 injuries and about 1,100 deaths
    attributed to red light running.
  • According to FHWA survey study, 44 of the red
    light running were attributed to traffic light
    view blockage.
  • Countermeasures have been studied and cameras
    cannot help reduce red light running due to
    visibility blockage
  • Smith (2001) confirmed that advanced warning
    signs to forewarn drivers approaching a
    signalized intersections reduces significantly
    red light running.

7
CHAPTER 2 DRIVING SIMULATORS
  • 2.1 UCF Driving Simulator
  • The driving simulator is an STS Mark-III system
  • Simulator Cab 5 channels of image generation.
  • Simview Graphical display software.
  • Mdyn Physical feeling of the driving.
  • Motion base Provides motion.

8
2.1 UCF Driving Simulator (continued)
  • Scenario Editor enables us to design scenarios.
  • APIs for reading real-time data Currently, APIs
    can read real-time data from Simview. The data
    include steering wheel, accelerator, brake, every
    cars speed and coordinates, with 30 HZ
    frequency.
  • Control Room with an emergency STOP button.
  • Real-time map showing the location of the
    simulator and the ambient traffic.

9
CHAPTER 3 EXPERIMENT METHODOLOGY
3.1 Horizontal visibility blockage scenario
SUB-SENARIO 2, BASE SUB-SCENARIO
10
3.1 Horizontal visibility blockage scenario
(Continued)

SUB-SENARIO 1, TEST SUB-SCENARIO
11
3.2 Vertical visibility blockage scenario
SUB-SENARIO 2, BASE SUB-SCENARIO
12
3.2 Vertical visibility blockage scenario
(continued)

SUB-SENARIO 1, TEST SUB-SCENARIO
13
3.3 Horizontal visibility blockage simulation
scenario design
  • Two design criteria are applied
  • Dropping velocity from 45 mph to 35 mph.
  • Dropping lanes from 2 in each direction to 1 in
    each direction.

STAGE 3
STAGE 2
14
3.4 Vertical visibility blockage simulation
scenario design
  • Two design criteria are applied
  • School bus makes a right turn slowly.
  • 1 lane per direction and high traffic volume in
    the opposite direction.

STAGE 3
STAGE 2
15
CHAPTER 4 THEORETICAL CALCULATIONS
4.1 Vertical visibility blockage
to be H2 LSV height 8.5 ft is used in the
experiment. H3 signal head height 21 ft is u
sed in the experiment (AASHTO).
H1 eye elevation equal to 3.75 ft (AASHTO)
w width of the intersection 40 ft (AASHTO)
L length of the vehicle taken 30 ft (AASHTO)
D Gap bet/ stop bar and intersection 10 ft
t standard reaction time 1.0 s (AASHTO)
a acceleration 10 ft/s2 (AASHTO)
X1 See figure X2 .See figure V 35 mp
h or 51.33 feet per second
16
4.2 Horizontal visibility blockage
CONCLUSION if AF Visibility blocka
ge
Condition
w intersection width 24 ft ( each lane is
assumed to be 12 ft) L vehicle length 30 ft
(AASHTO) D Gap bet/ stop bar intersectio
n 10 ft t reaction time 1.0 s (AASHTO) a
acceleration 10 ft/s2 (AASHTO)
AG Shown in the fig GF Shown in the fig.
v velocity 35 mph or 51.33 ft/sec
17
CHAPTER 5 Data collection method
5.1 Pilot Study
Preliminary data collection method
5 (SIM-LTV/SIM-PC)
N 10
5 (SIM-PC/SIM-LTV)
3 Tests
P-value0.138
  • Testing rear-end collisions between the SIM-PC
    and SIM-LTV (10 Vs.10) .
  • Testing the rear-end collisions between SIM-PC
    and SIM-LTV (5 Vs. 5).
  • Testing rear-end collisions SIM-LTV and SIM-LTV
    (5 Vs.5)

P-value0.157
P-value0.157
CONCLUSIONS
  • bias in the data collection.
  • marginal statistical difference between starting
    with PC and starting with LTV accident ratio with
    P-value 0.157.
  • A subject cannot drive more than 1 sub-scenario
    in each scenario

18
5.2 Sample size
95 C.I.
99 C.I.
N40 for each scenario
19
CHAPTER 6 EXPEIMENTS DATA OUTPUT
6.1 Raw data
  • X-Y coordinates of vehicles
  • Simulator car speed
  • Acceleration input
  • Brake input
  • Steering input

20
6.2 Derived data
6.2.1 Horizontal view blockage
1. Deceleration rate
2. Reaction delay time
21
3. Cruising velocity
4. Gap (ft) (sec)
5. Angular Velocity
22
6.2.2 Vertical view blockage
2. Cruising velocity
1. Reaction delay time
3. Deceleration rate
23
7. HORIZONTAL VIEW BLOCKAGE DATA ANALYSIS
7.1 Rear-end collision rate
CHI-SQUARE TEST
P-value 0.013
Statically significant difference between the
accident rates
24
7.2 Deceleration Rate
Vi Cruising Velocity Vf 5 mph
2 sample t-test
17.77 ft/sec2
22.23 ft/sec2
P-value 0.0027.3 Gap (ft)
2 sample t-test
75.6 ft
114.6 ft
P-value 0.01 25
7.4 Reaction delay time (sec)
  • Assumption For both Sub-scenarios

2 sample t-test
P-value 0.5510.05
7.5 Cruising velocity
2 sample t-test
34.30 mph
32.54mph
P-value 0.013
26
7.6 Impact velocity (mph)
Impact velocity LTV Impact velocity PC
Conclusion
  • More Rear- end collisions w/ LTV.
  • Accidents are more severe

27
7.7 Logistic regression
P-values
P-values 0.05 Start eliminating factors
28
7.7 Logistic regression (continued)
  • High Correlation Between PC LTV
  • Final Model does not include PC
  • When Critical ratio 1.375
  • Accident probability 0.5

1.375
29
7.8 Survey Analysis
Driving close to PC or LTV?
Seen or unseen Vehicle turning left?
30
7.10 Conclusions
  • Velocities following LTV PC
  • Gap following LTV
  • Deceleration rate following LTV PC
  • Impact Velocity higher
  • When Ratio 1.375
  • Survey Analysis shows
  • Frustration to pass LTV due to visibility blockage
  • Higher accident probability
  • Severe accidents following LTV

Potential rear-end collision with LTV
  • 50 had visibility problems
  • 35 Said they drive close to LTV in real life

All indications show that visibility blockage due
to LTV is serious
Possible future solution Adding a concave mirror
on the right side the road
31
8. VERTICAL VIEW BLOCKAGE DATA ANALYSIS
8.1.1 Red light running rate
CHI-SQUARE TEST
P-value 0.006 Statistical significant difference between red
light running rate
32
8.1.2 Deceleration rates
N 10 subjects from LSV Vs. N 18 subjects fr
om PC
2 Sample t-test P-value 0.97 0.05
No statistically significant difference
8.1.3 Reaction delay time
  • N18 Vs. N 10

2 Sample t-test P-value 0.073 0.05
No statistically significant difference
33
8.1.4 Velocity means
N 20 subjects from LSV Vs. N 20 subjects fr
om PC
2 Sample t-test P-value 0.43 0.05
No statistically significant difference
8.1.5 Gaps
  • N18 Vs. N 10

2 Sample t-test P-value 0.398 0.05
No statistically significant difference
34
8.1.6 Survey analysis
too late to stop following a
school bus and following a PC?
Driving close behind a school bus and a PC?
Same Visibility problem in daily life?
35
8.2 Suggested solution
8.2.1 Red light running rate
N 20 New Subjects
CHI-SQUARE TEST
Statistical significant difference
Potential Solution
P-value 0.047 36
8.2.2 Deceleration rates
P-value 0.408 0.05
8.2.3 Reaction delay time
P-value 0.649 0.05
37
8.2.3 Cruising Velocities
P-value 0.019 8.2.4 Gaps
P-value 0.273 0.05
38
8.2.5 Survey Analysis
Additional traffic signal pole
evaluation for real life.
traffic signal poles visibility
39
8.3 Conclusions
  • LSVs contribute to red light running.
  • Cruising velocities, gaps, deceleration rates,
    and reaction delay time were not statistically
    different
  • Fear of passing oversized vehicles
  • The solution is profitable
  • Survey
  • Profitability of additional signal pole
  • Real life visibility problem

40
9. CONCLUSIONS
  • LTVs contribute to rear-end collisions.
  • LTVs block the visibility for following PC.
  • Drivers behind LTV are frustrated
    smaller gaps higher velocity
  • Accidents are more severe.
  • Survey analysis - 50 suffered a visibility
    problem
  • - 35 drive
    close to LTVs in real life
  • LSVs contribute to red light running.
  • Velocities, gaps, deceleration rates, reaction
    delay time are the same

Fear of passing LSVs
3. From the survey (1) Real life problem, (2)
Visibility problem 4. Additional signal pole
decreases red light running 5. Additional traf
fic signal pole profitable according to survey
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