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Estimating Missing Path on Trajectories Trip by Using
Bluetooth Technology
Prof. Atsushi Fukuda
Assoc. Prof. Sorawit Narupiti
Assoc. Prof. Tetsuhiro Ishizaka
Miss. Pitchaya Panwan
Mr. Thana Potanon
With Prof. Masao Kuwahara
Bluetooth technology for TransportationReceiving Bluetooth (BT) signal by scanner at difference location has a possibility of a new
method to estimate traffic state such as travel timeBluetooth scanner, which is installed at the location along the road networks, can detect
Bluetooth-enabled devices (i.e. Mobile Phone, Navigators, headset etc.) from vehicle.
scanner
Travel time, route choice, OD matrix
Study area and location of Bluetooth detectors
BT detectors were set at 48 stations where are police box controlling traffic signal at intersection.
Data was collected 24 hours from 5/Feb. to 4/March, 2016.
11km
Police box
BT detector
107059
40682
16033
6094 2671 771 343 2470
20000
40000
60000
80000
100000
120000
3 4 5 6 7 8 9 10 up
Num
ber
of
trip
,(tr
ips)
No. of Station per trip
The Reliability of Bluetooth technology
The highest proportion of continuous station per trip is 3 stations (61%).
The maximum of continuous station per trip is 14 stations with 2 trips.
Therefore, there are many missing stations per trip.
61%
Challenging of Bluetooth technology for transportation
Problem
In case of Bluetooth detector cannot track MAC address from vehicle, we could not know a route of vehicle.
ObjectiveRecovering missing path of missing trip.
Cannot know where they’re going between these Bluetooth stations
Station
Study area and location of Bluetooth detectors
BT detectors were set at 48 stations where are police box controlling traffic signal at intersection.
Data was collected 24 hours from 5/Feb. to 4/March, 2016.
11km
Police box
BT detector
Data set on this experiment
All Trip
CompleteTrip
MissingTrip
1,398,329 trip
786,273 trip
612,056 trip
E F G H
I J K L
A B C D
E F G H
I J K L
A B C D
??
??
?
We cannot know, where a route of
traveler is.
How to track missing link
Conventional methodology Our methodology(Historical Travel time)
Select a route of shortest travel time from
missing links(routes)
Identify the selected shortest route as actual route
Calculate historical Travel timeon missing links(routes)
Calculate the actual travel time from BT data
Identify the route of minimum difference of travel time as
actual route
Sample Travel time data set for estimation of link 26-37
0:00:00
0:00:43
0:01:26
0:02:10
0:02:53
00:
00
02:
00
04:
00
06:
00
08:
00
10:
00
12:
00
14:
00
16:
00
18:
00
20:
00
22:
00
Trav
el t
ime
(min
s)
Time by day (hour)
MON
SUN
How to track missing link
How to track missing link
Our methodology
Historical Travel time There are 6 possible links to travel from D to I1) D – E – B – C – F – I (Route 1, 24 mins)
2) D – G – H – E – F – I (Route 2, 17 mins)
3) D – E – F – I (Route 3, 8 mins)
4) D – G – H – I (Route 4, 14 mins)
5) D – E – H – I (Route 5, 11 mins)
6) D – G – H – E – B – C – F – I (Route 6, 33 mins)
0:02
FE
C
D
IHG
B0:08
0:02
0:06 0:03
0:04
A0:04
0:04
0:06
0:05
0:06
0:047:00 AM
7:10 AM
Actual travel time from D to I1) D – I (10 mins)
How to track missing link
Conventional methodology
shortest distance shortest Travel time
0:02
FE
C
D
IHG
B0:08
0:02
0:06 0:03
0:04
A0:04
0:04
0:06
0:05
0:06
0:047:00 AM
7:10 AM
A
A
E
B
DC
Data set on this experiment
• Proportion of missing station from Missing trip data
0
50,000
1,00,000
1,50,000
2,00,000
2,50,000
3,00,000
1 2 3 4 5 6 7 8 up
trip
s
missing station
(25%)
(35%)
(14%)
FE
C
D
IHG
BA
Missing 2 station
How to verify
Original Complete Trip
Delete some stations of Bluetooth detector
Compare Original Complete trip with New
complete trip
Investigate Missing station by each method
A B C D E
A D E
A D E
A B C D E
B HCheck it same or not
? ?? ?
The accuracy of each methodology to estimate missing station on each trip
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
1 sta. 2 sta. 3 sta.
% A
ccura
cy o
n T
raje
ctory
station missed/trip
Historical Travel Time
Shortest Travel Time
Shortest Distance
Characteristic of missing link estimation
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60
Per
cent
Time (mins.)
Percent Correction and Percent error on each
time duration
correct
wrong
CONCLUSIONS
The most applicable method in terms of accuracy:1. The shortest travel time method
2. The historical travel time method and
3. the last one is shortest distance method.
In the rough estimation to multiply the percentage of missing link by each missing station and percentage of recover,➢52 % was recovered from all of missing links
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