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ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM ON A GERMAN AUTOBAHN
Steven BoicePortland State University
M.S. Civil Engineering Candidate
A Thesis defense presented in the partial fulfillment of the requirements for the degree of
MASTER OF SCIENCEin
CIVIL ENGINEERING
July 28, 2008
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN2
Presentation Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN3
Presentation Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN4
IntroductionVariable Speed Limit System Speed limits that change based on real time road, traffic, and weather
conditions – Road
• Slippery pavement, visibility– Traffic
• Density, speed, truck percentages – Weather
• Rain, snow, ice, fog Speed limits, advisories, regulatory prohibitions presented to drivers via
overhead gantries– Sign centered over each lane– Enforced via radar/camera
Speed limit changes based on series of algorithms Speed limits change in order to:
– Postpone or prevent freeway breakdown– Reduce shock speeds– Increase lane homogeneity (speed/flow)– Increase safety– Increase capacity
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN5
IntroductionVariable Speed Limit System Speed limits, advisories, regulatory prohibitions presented to drivers via
overhead gantries– Sign centered over each lane
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN6
IntroductionThesis Objective
Address VSL impacts on key traffic flow parameters– Bottleneck location/reoccurrence– Bottleneck properties (shock speed, pre-queue
flow, queue discharge flow)– Lane harmonization (flow/speed)
Address by conducting empirical before/after analysis on a German Autobahn– Use real data collected from roadway sensors
along Autobahn 99 with VSL in and out of operation
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN7
Variable Speed Limit: Concept
Maintain constant flow
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN8
IntroductionThesis Motivation
VSL - Germany, United Kingdom, Netherlands, Australia– Large emphasis on safety
– Large decrease in rear end crashes
– Large decrease in speed differential
– 20-30% reduction in crash rates (Germany)
– 30% reduction in injury crashes (M25 U.K.)
– Little emphasis on impacts of traffic flow parameters
– 15% increase in shoulder lane (M25 U.K.)
– Increase in weekday traffic volumes (M25 U.K.)
– No improvement in freeway performance (A2 Netherlands)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN9
IntroductionThesis Background
Graduate Research Assistant– Intelligent Transportation Systems Laboratory
• Empirical Analysis of German and U.S. traffic sensor data and impact on Driver Assistance Systems
o Funded by BMWo Analysis of A9
Rodger Lindgren– Analysis of A5
“Connections” allowed for access to A99 data Opportunity to compare US and German
freeways
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN10
Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN11
Study AreaAutobahn 99 - Munich, Germany
A99Study Area
A99 = ¾ ring around City of Munich, Germany
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN12
Study AreaAutobahn 99 Constructed in 1930’s Total 41 kilometers (A995 to A96) ¾ ring around city of Munich Considered one of busiest roadways in Europe
– ADT = ? No ramp metering Connects roadways to City of Munich
– A96– A8– A92– A9– A94– A995
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN13
Study AreaA99 Site Facts
Parameter Autobahn 99
Northbound Southbound
Length 15.6 km 16.3 km
Cross section 2-4 lanes 2-4 lanes
Hard shoulder Yes Yes
ADT ? ?
Speed limit Passenger cars - Only when VSL active
Trucks – 80km/hr (all time)
Passenger cars - Only when VSL active
Trucks – 80km/hr (all time)
Ramps 3 off/4 on 4 off/3 on
Mainline detectors (dual loop) 13 14
Ramp detectors (dual loop) 5 6
Detector spacing 320 m – 2,917 m 505 m – 2,250 m
VSL sign gantries 10 12
VSL sign gantry spacing 1,070 m – 2,030 m 663 m – 2,250 m
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN14
Study AreaAutobahn 99
Northbound
Southbound
945125013576261280146015401075
2197 1130 1720 2030 1629 1464 1120 1130 320 750 1300
60 70 80 90 110 120 130 140 150 170 190 210 220 232
70 780 772 760 750 740 730 720 714 210 710 690
60 70 80 90 110 120 130 140 150 170 190 210
780 770 760 750 740 730 720 714 710 690
(MQ)
(AQ)
(AQ)
(MQ)
(m)
786
Legend:
dual-loop detector station variable message sign gantry hard shoulder
720
468930225016501110(m)290 37 37
3730
(hard shoulder) Lane opened in dense traffic
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN15
Study AreaAutobahn 99
Southbound
945125013576261280146015401075
60 70 80 90 110 120 130 140 150 170 190 210 220 232
60 70 80 90 110 120 130 140 150 170 190 210
(MQ)
(AQ)
Legend:
dual-loop detector station variable message sign gantry hard shoulder
468930225016501110(m)290 37 37
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN16
Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN17
MethodologyA99 Data Summary
Detector data
DataFlow (cumulative over 1
minute)
(lane and vehicle specific)
Velocity (averaged over 1 minute)
(lane and vehicle specific)
Data availability
October 10, 2003-October 25, 2003
November 1-November 30, 2003
(57 days)
Variable Message Sign DataData Speed Limit
Driver Information
Warnings/Prohibitions
Data Availability October 10, 2003-October 24, 2003
November 11, 2003-November 30, 2003
System off October 25, 2003-November 10, 2003 (17 days)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN18
MethodologyA99 Data Summary
Detector Data Availability
Days with VSL Days without VSL
Weekday Weekend Weekday Weekend
24 10 7 5
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN19
MethodologyTransformed cumulative curves Transformed cumulative curves (e.g. Newell, Cassidy & Windover)
– Vehicle count
– Time-averaged speed
• Transformations to heighten visual resolution:o Oblique axiso Horizontal shift with vehicle conservation
o Retain highest level of resolution (one-minute)o Identify bottleneck activations and deactivations.
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN20
Bottleneck: Definition
An “active” bottleneck is a restriction that separates upstream queued traffic from downstream un-queued traffic
An “active” bottleneck is de-activated when there is either a decrease in demand or when a queue spills back from a downstream bottleneck
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN21
MethodologyTransformed Cumulative Curves
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
11,000
14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00
Time
N(x
,t)
Cu
mu
lati
ve
Co
un
t
N(x,t)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN22
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
11,000
14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00
Time
N(x
,t)
Cu
mu
lati
ve C
ou
nt
MethodologyTransformed Cumulative Curves
N(x,t)-q0t´
N(x,t)
q0=5180 vph
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN23
MethodologyTransformed Cumulative Curves
14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00
Time
N(x
,t)
Cu
mu
lati
ve C
ou
nt
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
11,000
N(x,t)-q0t´
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN24
MethodologyTransformed Cumulative Curves
14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00
Time
N(x
,t)
Cu
mu
lati
ve C
ou
nt
-300
-250
-200
-150
-100
-50
0
N(x,t)-q0t´
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN25
MethodologyQueuing Diagram
x1 x2
Ref. Veh. Trip Time
Number
Trip Timej
Time, t
j
t1
Travel DirectionN(xj,t)N(x1,t)
N(x2,t)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN26
MethodologyQueuing Diagram
ExcessAccumulation
x1 x2
Time, t
Travel DirectionN(xj,t)
Excess Travel Time=Delay
N(x1,t)
N(x2,t)
t2
k
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN27
Sou
thbo
und
945
1250
1357
626
1280
1460
1540
1075
6070
8090
110
120
130
140
150
170
190
210 2
2023
2
6070
8090
110
120
130
140
150
170
190
210
(MQ)
(AQ)
468
930
2250
1650
1110
(m)
290
3737
MethodologyTime Space Diagram
Spe
ed (
km/h
r)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN28
MethodologyTime Space Diagram
War
ning
/Pro
hibi
tion
(km
/hr)
1 = Speed 60 km/hr 2 = No passing Trucks3 = 4=
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN29
MethodologyFlow - Occupancy
All Lanes (Det. 130)
0102030405060708090
100
0 50 100 150 200
Occupancy - 5 min avg (%)
Flo
w (
vp
m)
Daily 7:40-8:00
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN30
Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN31
Analysis
– bottleneck location/reoccurrence
– Bottleneck characteristics• Shock speed, prequeue, queue discharge
– Lane harmonization (flow/speed)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN32
Go through 1 Bottleneck Diagnosis– Show audience how it is done
• Walk them through October 16, 2003 southbound– Include slides similar to A9 slides (included for
June 27, 2002)– Show how shock speed, pre-queue, and queue
discharge flows are calculated (see A9 slides)– Diagnosis
• Walk audience through 1 diagnosis– Walk audience through what VSL system was
doing
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN33
Speeds Northbound A9June 27, 2002
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN34
Speeds Northbound A9June 27, 2002
1
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN35
Bottleneck Activation June 27, 2002Station 380
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
Station 380 + Off Ramp
-50
50
150
250
350
450
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time
420
390
380off
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN36
Bottleneck Activation June 27, 2002Stations 380–390–420
-50
50
150
250
350
450
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time @ station 420
N(x
,t)
- q
0t
420
390
380off
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
Station 420 + On Ramp
Station 390
Station 380 + Off Ramp
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN37
-50
50
150
250
350
450
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time @ station 420
N(x
,t)
- q
0t
420
390
380off
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
15:21@ Station 390
15:21@ Station 380
Flow
Reduction
@380
Bottleneck Activation June 27, 2002Stations 380–390–420
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN38
380
15:15 15:20 15:25 15:30
Time
15:21
89 km/h
70 km/h
V(3
80,t
)-b
0t′,
b0=
3300
km
/hr2
Bottleneck Activation June 27, 2002Station 380 Speed
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN39
-50
50
150
250
350
450
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time @ station 420
N(x
,t)
- q
0t
420
390
380off
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
15:24@ Station 420
15:21@ Station 390
15:21@ Station 380
Flow
Reduction
@380
380
55200
55400
55600
15:15 15:20 15:25 15:30
Time
15:2189
70
V(3
80,
t)-b
0t′
, b0=
3300
km
/hr2
V(3
90,
t)-b
0t′
, b0=
4335
km
/hr2
390
98120
98170
98220
15:15 15:20 15:25 15:30Time
15:21
80 41
420
95010
95060
95110
15:15 15:20 15:25 15:30Time
V(4
20,
t)-b
0t′
, b0=
4850
km
/hr2
15:2492
65
Bottleneck Activation June 27, 2002Stations 380–390–420
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN40
Bottleneck Activation June 27, 2002
630
540
29400
29600
29800
15:15 15:20 15:25 15:30 15:35 15:40 15:45
Time
V(5
40,
t)-b
0t′,
b0=
4550
km
/hr2
15:349739
560
36420
36520
36620
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
60,
t)-b
0t′,
b0=
3550
km
/hr2
15:4183 43
580
34180
34280
34380
34480
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
80,
t)-b
0t′,
b0=
3650
km
/hr2
15:4287 43
600
32400
32500
32600
32700
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
630
41450
41650
41850
15:45 15:50 15:55 16:00 16:05 16:10 16:15
Time
V(6
00,
t)-b
0t′
, b0=
3450
km
/hr2
15:47
72 38
V(6
30,
t)-b
0t′
, b0=
3100
km
/hr2
15:5893 20
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN41
Bottleneck Activation June 27, 2002
15:21
15:24
15:34
15:4115:42
15:47
15:58 630
1
540
29400
29600
29800
15:15 15:20 15:25 15:30 15:35 15:40 15:45
Time
V(5
40,
t)-b
0t′,
b0=
4550
km
/hr2
15:349739
560
36420
36520
36620
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
60,
t)-b
0t′,
b0=
3550
km
/hr2
15:4183 43
580
34180
34280
34380
34480
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
80,
t)-b
0t′,
b0=
3650
km
/hr2
15:4287 43
600
32400
32500
32600
32700
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
630
41450
41650
41850
15:45 15:50 15:55 16:00 16:05 16:10 16:15
Time
V(6
00,
t)-b
0t′
, b0=
3450
km
/hr2
15:47
72 38
V(6
30,
t)-b
0t′
, b0=
3100
km
/hr2
15:5893 20
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN42
-300
-200
-100
0
100
200
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time
N(x
,t)
- q
0t
380
350
340
320
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
Station 350
Station 320 + Off-Ramp
Station 340
Station 380 + On-Ramp
Time @ station 380
Bottleneck Activation June 27, 2002Stations 320–340–350–380
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN43
-300
-200
-100
0
100
200
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time
N(x
,t)
- q
0t
380
350
340
320
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
15:21@ Station 380
Flow Reduction@380
Time @ station 380
Bottleneck Activation June 27, 2002Stations 320–340–350–380
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN44
-300
-200
-100
0
100
200
14:45 14:50 14:55 15:00 15:05 15:10 15:15 15:20 15:25 15:30 15:35 15:40 15:45 15:50
Time
N(x
,t)
- q
0t
380
350
340
320
N(x,t)-q 0t′,
q0=
51
70
ve
h/h
r
15:23@ Station 350
15:27@ Station 320
15:26@ Station 340
15:21@ Station 380
Flow Reduction@380
Time @ station 380
350
40500
40600
40700
15:15 15:20 15:25 15:30Time
15:23
84
84
V(3
50,
t)-b
0t′
, b0=
4200
km
/hr2
340
22320
22370
22420
15:15 15:20 15:25 15:30 15:35 15:40 15:45
Time
15:26
99
97
V(3
40,
t)-b
0t′
, b0=
5600
km
/hr2
320
19690
19740
19790
15:15 15:20 15:25 15:30 15:35 15:40 15:45
Time
15:27
105
104
V(3
20,
t)-b
0t′
, b0=
6000
km
/hr2
Bottleneck Activation June 27, 2002Stations 320–340–350–380
Time630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN45
Active bottleneck located between detectors 380 and 390.
Activated at 15:21. Queue propagated as far as
detector 630. Unrestricted traffic downstream.
Bottleneck Activation June 27, 2002
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN46
Bottleneck ActivationJune 27, 2002
Direction of Travel
15:21 19:40
17:40
18:44
17:28
17:35
17:38
15:24
15:34
15:4115:42
15:47
15:58
19:18
1
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN47
Bottleneck ActivationJune 27, 2002
Direction of Travel
15:21 19:40
17:40
18:44
17:28
17:35
17:38
15:24
15:34
15:4115:42
15:47
15:58
19:18
1
2
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN48
Direction of Travel
15:21 19:40
17:40
18:44
17:28
17:35
17:38
15:24
15:34
15:4115:42
15:47
15:58
19:18
Bottleneck ActivationJune 27, 2002
1
2
3
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN49
Direction of Travel
15:21 19:40
17:40
18:44
17:28
17:35
17:38
15:24
15:34
15:4115:42
15:47
15:58
19:18
Bottleneck ActivationJune 27, 2002
1
2
34
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN50
Bottleneck Activation June 27, 2002Stations 380–390–420
N(420,t)
N(390,t)
N(380,t)0
100
15:00 16:00 17:00 18:00 19:00
Time
N(x,t)-q0t
, q0=
51
78
ve
h/h
r
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN51
Bottleneck Activation June 27, 2002
N(420,t)
N(390,t)
N(380,t)0
100
15:00 16:00 17:00 18:00 19:00
Time
N(x,t)-q0t
, q0=
51
78
ve
h/h
r
15:2
1 17:3
5
17:4
0
18:4
5
19:1
8
1
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN52
Bottleneck Activation June 27, 2002
N(380,t)0
100
15:00 16:00 17:00 18:00 19:00
Time
N(x,t)-q0t
, q0=
51
78
ve
h/h
r
15:2
1 17:3
5
17:4
0
18:4
5
19:1
8
1
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN53
Bottleneck Activation June 27, 2002
N(380,t)0
100
15:00 16:00 17:00 18:00 19:00
Time
N(x,t)-q0t
, q0=
51
78
ve
h/h
r
15:2
1 17:3
5
17:4
0
18:4
5
19:1
8
5510
vph
5370 vph
1
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN54
Bottleneck Activation June 27, 2002
N(380,t)0
100
15:00 16:00 17:00 18:00 19:00
Time
N(x,t)-q0t
, q0=
51
78
ve
h/h
r
15:2
1 17:3
5
17:4
0
18:4
5
19:1
8
5510
vph
5370 vph
5410 vph
1 4
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN55
Bottleneck Activation Northbound A9Outflow Summary at 380
Day
Date
Pre-
Queue Flow
Pre-Queue
Standard Deviation
Bottleneck
Outflow Duration
Bottleneck Outflow
Bottleneck Outflow
Standard Deviation
Flow Drop
Wed 6/27/2002 5510 10.53 2:13 5370 5.8 -3% 6/27/2002 0:33 5410 6.5
Thu 6/28/2002 5800 11.22 1:41 5545 6.3 -4% 6/28/2002 0:55 5266 6.3 6/28/2002 0:30 5359 4.6 6/28/2002 1:46 5393 6.8
Mon 7/2/2002 5972 5.58 1:34 5177 6.2 -13% Tue 7/3/2002 5835 8.31 0:11 5485 4.9 -6%
7/3/2002 1:40 5017 5.2 Wed 7/4/2002 3:30 5551 6.8 Thu 7/5/2002 5527 9.43 1:22 5429 7.0 -2%
Mean: 5620 5370 -5% Standard Deviation: 320 160
630
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN56
Bottleneck Activation – October 16, 2003
Sou
thbo
und
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN57
Sou
thbo
und
9:53
8:029:44
8:18
8:25
9:29
9:28
9:497:56
8:55
10 km/hr
Pre-queue Flow = 4630 Median lane = 1848 Center lane = 1835 Shoulder lane = 948Queue Discharge Flow = 4134
Queue Discharge Flow = 4332
2
1
1 2
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN58
-200
-100
0
100
200
300
400
500
7:00 7:15 7:30 7:45 8:00 8:15
Time @ Station 60
N(x
,t)-
400
0(t
')
Bottleneck Diagnosis
Sou
thbo
und
70
60
90
80
110
120
130
140
150
170
190
210220
232
Station 130
Station 120
Station 110
Station 140 + Off Ramp – On Ramp
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN59
-200
-100
0
100
200
300
400
500
7:00 7:15 7:30 7:45 8:00 8:15
Time @ Station 60
N(x
,t)-
400
0(t')
Bottleneck Diagnosis
Flow Reduction @ Station 130Uninterrupted flow between Stations 130 and 140
7:49 @ Station 130
Sou
thbo
und
70
60
90
80
110
120
130
140
150
170
190
210220
232
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN60
Bottleneck Diagnosis
Continue diagnosis details for October 16 here– Similar to A9 as shown in previous slides
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN61
Bottleneck Diagnosis
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN62
Bottleneck Diagnosis
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN63
VSL Dynamics
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN64
VSL Dynamicsposted speed
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN65
VSL DynamicsWarnings/prohibitions
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN66
VSL Dynamicstext information
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN67
VSL DynamicsPosted speed vs Measured speed
0
20
40
60
80
100
120
140
18:3
018
:45
19:0
019
:15
19:3
0
Time
Sp
ee
d (
km
/hr)
120_AQ 120_MQ 110_AQ 110_MQ
VSL
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN68
Measured speed vs warnings prohibitions
0
20
40
60
80
100
120
140
160
180
6:00 6:15 6:30 6:45 7:00 7:15 7:30 7:45 8:00 8:15 8:30 8:45 9:00 9:15 9:30 9:45 10:00
10:15
10:30
10:45
11:00
11:15
11:30
11:45
12:00
0
1
2
3
4
5
6
7
8
9
10
11
12
13
210_MQ
210_AQ
Warnings/prohibitions
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN69
Sign AQ 215a = -1 km/hr
Sign AQ 214 = -6 km/hr
Bottleneck activation between 57-53Bottleneck shift upstream between 53-47
Bottleneck deactivated
Detector speed minus posted speed
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN70
Average trucks speeds +10-20 km/hr above mandatory 80 km/hr
Speed Variance: Trucks Detector speed (actual) – Mandatory truck speed (80 km/hr)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN71
Speed Variance: Trucks Detector speed (actual) – Variable speed (posted)
Sign AQ 215a = -5 km/hr
Sign AQ 214 = -13 km/hr
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN72
Speed compliance
Station 120_80km/hr
0
20
40
60
80
100
120
140
160
Lane
1 Ove
rall
Lane
1 Tru
cks
Lane
1 Car
s
Lane
2 Ove
rall
Lane
2 Tru
cks
Lane
2 Car
s
Lane
3 Ove
rall
Lane
3 Tru
cks
Lane
3 Car
s
Lane
4 Ove
rall
Lane
4 Tru
cks
Lane
4 Car
s
Overa
ll
Truck
sCar
s
Av
g. S
pee
d (
km
/hr)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN73
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN74
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN75
Flow-Density
0
1000
2000
3000
4000
5000
6000
0 10 20 30 40 50 60 70 80 90 100
Density (veh/km)
Flow
(vph
)
Det. 47 Sign Changes
Flow – Density Relationship: Detector Station 47/Message Sign AQ 214
1
2 4
3
5
N-V Curve
-19600
-19550
-19500
-19450
-19400
-19350
-19300
-19250
-19200
5:50 6:05 6:20 6:35 6:50 7:05 7:20
Time
N(x
,t)-
qo
(t')
q
o =
3800 v
ph
12700
12900
13100
13300
13500
13700
13900
V(x
,t)-
bo
(t')
b
o =
3900 k
m/h
r2
Det 47 N Det 47 V
6:14 – Speed reduced to 80 km/hr.
6:00 – Speed limit activated with posted speed of 120 km/hr.
7:05 - Speed limit de-activated. No passing restriction changes to “Congestion” indication on sign.
2448 vph
3497 vph
4197 vph
4002 vph3728 vph
3155 vph
5:55 – No passing for trucks prohibition activated 6:09 – Speed reduced to 100 km/hr
6:36 Speed reduced to 60 km/hr
92 km/hr
83 km/hr
77 km/hr 62 km/hr
76 km/hr
53 km/hr
Bottleneck activation between 57-53
120 km/hr100 km/hr80 km/hr60 km/hr
No Passing “TRUCKS ONLY” Congestion
Flow-Density points were plotted for each state at which the variable speed changed and also for constant states for detector station 47. As can be seen, the speed decreases for each point (1-5)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN76
Sou
thbo
und
9:53
8:029:44
8:18
8:25
9:29
9:28
9:497:56
8:55
10 km/hr
Pre-queue Flow = 4630 Median lane = 1848 Center lane = 1835 Shoulder lane = 948Queue Discharge Flow = 4134
Queue Discharge Flow = 4332
2
1
1 2
WITH VSL
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN77
8:34
9:05
8:13
8:07
8:02
7:56
8:43
8:49 9:008:27
8:54
7:48
7:278:33
9:41
8:26
8:34 8:57 9:16
8:53
8:18 8:21
9:189:078:27 8:378:22
8:41
7:47 8:00
9:168:38 8:50
9:32
7:358:10
15 km/hr 20 km/hr
5 km/hr
Pre-Queue Flow = 4680 Median lane = 1740 Center lane = 1740 Shoulder lane = 1200Queue Discharge Flow = 4560
8:531
2
3
4
1
2 Pre-Queue Flow = 5340Queue Discharge Flow = 5100
WITHOUT VSL
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN78
AnalysisBottleneck Location/Reoccurrence
Include map showing all BN locations for NB and SB (next slide)
Include whether VSL was on/off Include aerial for popular locations Need to show no reoccurring and that VSL had
no impact on location Cant compare reoccurring, but still can compare
with and without VSL
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN79
AnalysisBottleneck Location/Reoccurrence
Southbound
Legend
VSL ON VSL OFF
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN80
AnalysisBottleneck Location/Reoccurrence
11 days of detector data with VSL system out of operation (Before Comparison)– October 25, November 1-10– 6 total weekdays of detector data with VSL system off
Statistical validness? Southbound
– Isolated bottlenecks on 3 of the days with VSL system off
– Isolated bottlenecks on 11 of the days with VSL system on
• All Non-re-occurring
• Correlated with median and shoulder lane closures and speed zone
o Construction? Maintenance of the system?
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN81
Bottleneck Characteristics
Day Pre-Queue Flow (vphpl)
Queue Discharge Flow (vphpl)
Change (%)
VSL On
October 15, 2003
October 16, 2003 1910 1610 -14%
Average x x x
VSL Off
November 2, 2003
November 3, 2003 1833 1580 -0.16
Average x x x
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN82
Consider showing figure to illustrate differences in bottleneck characteristics with and without VSL
Compare to other German, US, Canada freeways
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN83
AnalysisShock speed
Show 1 example with and without VSL Include table listing shock speeds of BN’s
– With and without VSL Are they different?
– Speed– Length– Number per day
Oscillation map? Did VSL dampen shocks
– Advise drivers upstream
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN84
Bottleneck Activation June 27, 2002
15:21
15:24
15:34
15:4115:42
15:47
15:58 630
1
540
29400
29600
29800
15:15 15:20 15:25 15:30 15:35 15:40 15:45
Time
V(5
40,
t)-b
0t′,
b0=
4550
km
/hr2
15:349739
560
36420
36520
36620
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
60,
t)-b
0t′,
b0=
3550
km
/hr2
15:4183 43
580
34180
34280
34380
34480
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
V(5
80,
t)-b
0t′,
b0=
3650
km
/hr2
15:4287 43
600
32400
32500
32600
32700
15:30 15:35 15:40 15:45 15:50 15:55 16:00
Time
630
41450
41650
41850
15:45 15:50 15:55 16:00 16:05 16:10 16:15
Time
V(6
00,
t)-b
0t′
, b0=
3450
km
/hr2
15:47
72 38
V(6
30,
t)-b
0t′
, b0=
3100
km
/hr2
15:5893 20
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN85
Analysis
Show corridor oscillation for October 16 to help illustrate what a shock wave is
-200
0
200
400
600
800
1000
1200
1400
7:00 7:14 7:28 7:43 7:57 8:12 8:26 8:40 8:55
det. 60
det. 70
det. 80
det. 90
det. 110
det. 120
det. 130
det. 140
det. 150
det. 170
det. 190
det. 210
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN86
Shock Summary
Day Shock Speed (km/hr)
Shock Distance (km)
VSL On
October 15, 2003
October 16, 2003 1910 1610
Average x x
VSL Off
November 2, 2003
November 3, 2003 1833 1580
Average x x
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN87
Analysis – lane harmonization
Show 1 example with and without VSL Concentrate on pre-queue, during queue What are trucks doing? Speeds
– Compliance?
– What is difference in speeds across all lanes?
– Total flow for lanes What are the differences with and without VSL?
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN88
Average daily speeds on 5 days before VSL went down, 5 days with VSL down, then 5 after VSL came back on
Measure speeds at 4 stations (110-140) Need to label when and what VSL speed limits
are
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN89
Do same thing with daily standard deviation as with average speed
Station 12010.16 & 11.3
0
10
20
30
40
50
60
70
80
1:00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:0
011
:00
12:0
013
:00
14:0
015
:00
16:0
017
:00
18:0
019
:00
20:0
021
:00
22:0
023
:00
0:00
Time
Sta
nd
ard
Dev
iati
on
Sp
eed
(km
/hr)
No VSL VSL
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN90
Station 12010.16 & 11.3
0
10
20
30
40
50
60
70
80
1:00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:0
011
:00
12:0
013
:00
14:0
015
:00
16:0
017
:00
18:0
019
:00
20:0
021
:00
22:0
023
:00
0:00
Time
Sta
nd
ard
De
via
tio
n S
pe
ed (
km
/hr)
No VSL VSL 60 VSL 80 VSL Off
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN91
Summarize speeds at certain traffic states– Freeflow, dense, queue formation, congestion
Station 12010.16.03 & 11.3.03
8276 76 73
121115
10294
0
20
40
60
80
100
120
140
FreeFlow Dense Queue Formation Congested
Ave
rag
e S
pee
d (
km/h
r)
0
2
4
6
8
10
12
14
16
18
Sta
nd
ard
Dev
iati
on
Sp
eed
(k
m/h
r)
VSL Avg No VSL Avg VSL Std No VSL Std
Station 12010.16.03 & 11.3.03
42
65
8594
26
64
86
97
0
20
40
60
80
100
120
FreeFlow Dense Queue Formation Congested
Ave
rag
e F
low
(vp
m)
0
2
4
6
8
10
12
14
16
18
Sta
nd
ard
Dev
iati
on
Flo
w (
vpm
)
VSL Avg No VSL Avg VSL Std No VSL Std
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN92
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN93
Results
Empirical impacts of VSL system• Alteration of key traffic flow parameters
o Bottleneck location/reoccurrenceo Bottleneck properties (shock speed, pre-queue
flow, queue discharge flow)o Lane harmonization (flow/speed)
– Contribute to the minimal literature
– Potential applications on U.S. freeways • Current use in work zones
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN94
Show tables/figures summarizing results
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN95
Complications
Median and shoulder lane closures– Typical on weekdays
60 km/hr speed limit– Construction?
System unstable Limited ramp data, particularly at A9 and A94
interchanges High rates of detector failure/drift
– Vehicle conservation difficult Hardshoulder
– Difference in capacities
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN96
Outline
Introduction Study Area Methodology Analysis Results Outlook
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN97
Outlook
Continued empirical analysis and comparison with measurements on freeways in the U.S., Canada, and United Kingdom
Improved travel time estimation and forecasting:– Traffic management
– Traveler information
– Driver assistance systems Contribute to improved traffic flow models and freeway
operational strategies Opportunity to compare with previous findings using data
from German freeways (bottleneck capacity)
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN98
Acknowledgements
Dr. Robert Bertini Dr. Soyoung Ahn Dr. Klaus Bogenberger, Dr. Georg Lerner, Dr.
Hartmut Keller, and the BMW Group Christian Mayr and Frank Frischeisen of
Autobahndirektion Südbayern
ANALYSIS OF VARIABLE SPEED LIMIT SYSTEM
ON A GERMAN AUTOBAHN99
Thank you for your attention
http://www.its.pdx.edu/