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