A Comfort Measuring System for A Comfort Measuring System for Public Transportation Systems Public Transportation Systems

Using Participatory Phone Sensing Using Participatory Phone Sensing

Cheng-Yu Lin1, Ling-Jyh Chen1, Ying-Yu Chen1, and Wang-Chien Lee2

1Academia Sinica, Taiwan2The Pennsylvania State University at University Park, USA

What are people doing on the bus?What are people doing on the bus?

Comfort Comfort does matter!!does matter!!Comfort Comfort does matter!!does matter!!

How to measure it?How to measure it?

Questionnaire/Interview

Professional Instruments

Problems: Cost, Timeliness, and Scalability

Problems: Cost, Timeliness, and Scalability

ParticipatoryParticipatory PhonePhone SensingSensing

• A new sensing paradigm to exploit the sensing capabilities of modern smart phones to gather, analyze, and share local knowledge of our surroundings (e.g., CenseMe, SoundSense, Nericell)

• It does not rely on dedicated sensing infrastructures and the top-down model of data collection.

• It is more penetrative, and encourages participation at personal, social, and urban levels.Question: how about let’s combine the

participatory phone sensing and top-down data collection model?

Question: how about let’s combine the participatory phone sensing and top-down

data collection model?

ComfortComfort MeasurementMeasurement SystemSystem

Public Transportation SystemsParticipants

Data Mashup and Statistics

Sensing data(e.g. locations, acceleration, and time)

Authorized data(e.g. bus trajectories and vehicle properties)

Scoring and ranking results

• Goal: to evaluate the comfort level of public transportation systems

Our ContributionsOur Contributions

• We propose the Comfort Measurement System that exploits participatory phone sensing (bottom-up model) and the authorized data (top-down model).

• We prototype a CMS, called TPE-CMS, to evaluate the public bus transportation service in Taipei City.

• We conduct a 70-day experience to reveal the insights of the Taipei e-bus system.

• Exploit the GPS and G-sensor (3-axis accelerometer) of modern smart phones

• Calculate comfort index by following ISO 2631

Weighted Average Acceleration Level

uncomfortablecomfortable

Phone SensingPhone Sensing

• No need to reinvent the wheel!• We take advantage of existing real-time bus

tracking systems, which are available in many major cities world-wide (e.g., Boston, Cambridge, Seattle, and Taipei).

• It contains the bus trajectory, route number, operating agency, and the other useful data.

• This may be the most challenge, because you have to talk to the authority

Authorized DataAuthorized Data

Data MashupData Mashup

User Trajectory

Bus Trajectory

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5Di = average ( , )k k

We suppose the user is on the b-th bus, s.t. b = arg Min Di

ImplementationImplementation

4,028 buses, 287 routes, 15 agencies, and 1 sample per minuteVProbe

http://VProbe.org/TPE-CMS/

ExperimentsExperiments

• Period: 2010/03/15 – 2010/07/22• 15 volunteers

– Collect trajectory and vibration traces of Taipei buses using Android phones

– Keep a memo of the ground truth (i.e., the agency, route, and license number of their bus rides)

• 425 trajectories collected, involving 12 agencies and 3 types buses

Results(1/3) - Results(1/3) - Trajectory Matching ResultsTrajectory Matching Results

Results(2/3) -Results(2/3) -The Statistics based on Buses TypesThe Statistics based on Buses Types

• Light buses are uncomfortable.• No significant difference between the standard buses and

the low-floor ones.

• The most comfortable and uncomfortable agencies are exactly the same as the ones reported in the survey made by Taipei Department of Transportation.

Results(3/3) - Results(3/3) - The Statistics based on Buses AgenciesThe Statistics based on Buses Agencies

ConclusionsConclusions

• We present a Comfort Measuring System for public transportation systems, and prototype the system in Taipei city.

• The CMS system can be deployed in any cities, as long as there are volunteering participants and there are authorized transportation data available.

• Work on analyzing other factors that affect comfort levels is ongoing (e.g., road conditions, drivers’ behavior, and traffic congestion).

Thanks for Your Attention!

http://VProbe.org/http://VProbe.org/http://VProbe.org/TPE-CMS/http://VProbe.org/TPE-CMS/