1. Analysing a road network in Greater Manchester from
data collected by Bluetooth passive sensors.
Presented by - Mayank Balakrishnan (Consultant, ITDP)
MSc Transport Planning and The Environment (University of Leeds)

2. Outline
• Objectives
• What are Bluetooth Passive sensors?
• Study area
• Analysing the sensitivity of the devices to accidents
• Resilience Analysis
• Effect of accident on adjacent road as well as on the upstream and
downstream side.
• integration of Bluetooth and Wifi.
• Applications

3. • Understanding the road infrastructure based Intelligent Transportation Systems
particularly pertaining to ATMS and ATIS.
• Analysing the reliability of Bluetooth technology in acquiring traffic data.
• Analysing the traffic behaviour of the network from the data collected with respect to
journey times against accidents.
• Giving an insight about the integration of two technologies (Bluetooth and Wifi) and its
applications.
Objectives

4. What are Bluetooth Passive Sensors?
• Bluetooth is a short range communication
protocol.
• Band width ranging between 2.4 to 2.5 GHz.
• High communication class types are considered
for transport.
• The Bluetooth Media Access Control Scanner
(BMS) identifies the different MAC; in this case the
journey times of the vehicles for a road network in
Manchester.
MAC ID

5. Study area
• London Road A6 route.
• 14kms in length from Downing Street/ Grosvenor
Street to Hazel Grove
• MAC IDs - MAC1041ST and MAC1078MR.
• Effect of accidents on the journey times occurring
along the A6.
• Over the A6010 which are placed with sensors
having MAC IDs MAC1076MR and MAC4037MR as
well as the Devonshire street both connecting the
A57.

6. Analysing sensitivity of the devices to accidents
Accident scenario
Date - 17th October 2014
Accident time – 14:45
Distance between sensors – 165 meters
Accident observed between sensors – MAC1088ST
and MAC1089ST
Graph showing steep rise in
journey time
.

7. Resilience of the network against accidents
• The performance of a particular system or a transportation system under unusual unexpected
circumstance and the outside assistance required for restoring it back in the original functional state (M.
Murray, 2006).
In transportation, resilience has the following dimensions
• Redundancy
• Diversity
• Efficiency
• Adaptability
• Mobility
• Safety
• Recovery
What is Resilience in transport?

8. Mobility
• Ability of the vehicles to move freely and easily from the origin to the destination.
• Calculated by; link speed and Volume/ Capacity ratio (V/C ratio).
• The total time observed where the average vehicle speed is less than its prescribed speed limit.
• The capacity (operational) of street is calculated using the speed flow curve and then used in the
equation.
Recovery
• Total time required to reduce the congestion.
• The speed of the vehicles to when it exceeds the respective speed limit of the street.
• V/C ratio to when it returns to its acceptable limit.

9. Resilience calculations with mobility
Accident scenario
Accident date – 17th of November 2014
Accident observed between sensors – MAC1089ST and MAC1088ST
Accident analysis time range – (14:30 – 16:00) 15 min interval
Hour Flow Journey Time Distance Speed
14:30 29 94 484 18.53
14:45 30 95 484 18.34
15:00 2 110 484 15.84
15:15 5 75 484 23.23
15:30 1 108 484 16.133
15:45 1 170 484 10.249
16:00 1 104 484 16.75
Total 69 756 - -
Average speed of the vehicles – 17.01km/hr
Prescribed speed limit over the A6 – 48km/hr
Time vehicles travelled less than the speed limit = 756 seconds
Drake well C2-Cloud Traffic Data, TFGM

10. Normal conditions
Date – 10th of November 2014
Time considered – (14:30 – 16:00) 15 min interval
Hour Flow Journey Time Distance Speed
14:30 22 78 484 22.33
14:45 23 81 484 21.51
15:00 39 77 484 22.63
15:15 38 85 484 20.5
15:30 24 89 484 19.57
15:45 31 81 484 21.51
16:00 28 111 484 15.7
Total 205 602 - -
Average speed of the vehicles – 20.54km/hr
Prescribed speed limit over the A6 – 48km/hr
Time vehicles travelled less than the speed limit = 602 seconds
Drake well C2-Cloud Traffic Data, TFGM

11. Conclusions to calculations
• Accident scenario has observed lesser vehicles with increased travel time and much lesser
speed indicating reduced mobility.
• The increase in the total number of vehicles in normal conditions is observed by 197%
whereas the total travel time is reduced by 26% with speed of vehicles improved by 20.75%.
0
20
40
60
80
100
120
140
160
180
14:30 14:45 15:00 15:15 15:30 15:45 16:00
Hour
Comparison
Normal Flow
Normal Time
Normal Speed
Accident Flow
Accident Time
Accident Speed

12. Analysing the effect of the accident on the adjacent road
• Accident 2 - 16th of October 2014
at 2pm on the Hyde Road at
junction with Devonshire Street.
• The vehicle passes the junction
and then collides with a pedal
cycle on the Devonshire Street.
Effect over the street between MAC4038MR and MAC1075MR
0
20
40
60
80
100
120
Accident Normal Accident Normal
Flow Time
15:00
• Similar match count observed, however the time in normal conditions is much less when compared
to the time of accident.
• A quote by Benjamin Franklin stated “Little strokes fell great oaks” which clearly relates to this
situation that although the accident was not a serious one, it did manage to increase the travel time
considerably mainly due to the site being a junction.

13. Analysing the effect of the accident on the
upstream and downstream side
0
5
10
15
20:00 20:15 20:30 20:45 21:00
HOUR
Match count
Downstream
Match count Upstream
Speed (m/s)
Downstream
Speed (m/s) Upstream
• The distance from one point to the other has a
greater effect on the travel time of vehicles than the
effects influenced by speed.
• Vehicles travel lesser distance in lesser time with
lower speeds as compared to vehicles travelling
longer distances with more time and higher
speeds.
• Wardop (1952) suggested that if the speed increases
by a greater proportion than the distance then it
results in lesser travel time and vice versa.
• In this case, the speed at the downstream side
increased by a lesser proportion than the distance
since it observes higher travel time.

14. Integration of Bluetooth and Wifi
(Part 2)
What is Wifi?
• It is a technology that uses radio waves through wireless LAN connecting devices and is
password protected for security measures.
•Wifi connects through a frequency of 2.5 to 5 ghz.
• It consists of an access point. This access point sends a wireless signal that is picked up
by any devices such as mobiles, laptops, computers.
The major disadvantage of integration of Bluetooth and wifi is interference problems with
collisions since both use approximately the same radio frequency bands causing dropped
packets.
Advantages with integration:
• High frequency is obtained with better connectivity.
• Increase in wireless range between devices.
• Data can be acquired at a faster rate.
• Larger amount of data can be acquired.

15. Applications
• In 2013, Portsmouth council began to use Bluetooth and Wifi sensors across
major streets for proactively managing jams and diversions, acquiring average
speeds, learning about road capacities and traffic behaviour.
• Apart from transport, the Aalborg city in Denmark have installed similar
sensors to analyse shopper and pedestrian behaviour.
• Bluetooth and wifi combined sensors have also been used in airports such as
Amsterdam Schiphol, Toronto Pearson, Dubai International and Manchester
Airport for acquiring passenger data.

16. An article on my thesis published in the ITS UK Review for July 2015

17. References
• Grant Muller and Usher (2013) Intelligent Transport System: The propensity of environmental
and economic benefits: Technology forecasting and social change. Vd – 82, pp 149-166.
• Murray- Tuite, P. M. (2006, December). A comparison of transportation network resilience
under simulated system optimum and user equilibrium conditions. In Simulation Conference,
2006. WSC 06. Proceedings of the Winter (pp. 1398-1405). IEEE.
• Reggiani, A. (2013). Network resilience for transport security: Some methodological
considerations. Transport policy, 28, 63-68.
• Berdica, K. (2002). An introduction to road vulnerability: what has been done, is done and
should be done. Transport Policy, 9(2), 117-127.