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BLUFAX APPLICATIONS
Donna Nelson, PhD
Marketing Director, Traffax Inc
240-447-8612
BluFax Technology
Distance
Each Bluetooth devices has a unique, but anonymous device ID
BluFax devices record:
ID of each detectable device.Time stamp ID detected.BluFax unit IDBluFax location coordinates.
BluStat Software:
Processes station data.Filters and processes data.Outputs graphics and results.User-configurable parameters.
Detection Zone
At least two units are required! Number of units and spacing depends on application.
Bluetooth MAC IDs
00:18:AF:4B:56:BDManufacturer code
Device ID
Device IDs are assigned by the manufacturer
No personal information
Not traceable to an individual
Compliant with IEEE standards
Federal requirements
Overcomes privacy concerns inherent in other technologies
BluFAX Portable Units
• Pelican weather resistant case
• Mounting brackets available
• 2 yrs data storage on internal card.
• 14+ days on AGS battery
• Data transmission via cellular modem once daily available.
Portable units
Antennas Omni-directional or directional
May be placed outside of case
Class 1 or class 2 antennae.
BluFax Anatomy 101
Powered by an AGS-type battery .Operates up to 14 days on a charge.
Internal GPS for location and time reference.
Stores up to 2 years data on a micro SD card. Readable with standard adapter
Standard configuration- Class 1 Bluetooth radio/antenna combination with a range of up to 100m.
Highlights of BluFax Portable Specifications
Comes packaged with BluStat Software.
Spatially-Based Concept
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Sensor ID
Device Location
MAC ID
Time
Travel time
O-D
Applications compare data collected by pairs of units to calculate travel time and speed between two points, called a SEGMENT.
Units are positioned to create segments that can be compared to obtain origin-destination information (A-B or AC).
BluFax Terminology
Sensor ID
Device Location
MAC ID
Time Stamp
Segment: Defined between two segments.
GD
A B C
EH
D
All BluFax applications build on the concept of comparing the time at which unique device IDs are detected by pairs of units.
Corridor: Defined by a series of segments, usually for speed or travel-time.
Station: BluFax unit.
O-D Pairs: Also defined by segments, but where the origin-destination or path followed is the primary focus.
APPLICATIONS…….
BluFAX has been used successfully for studies in the US and internationally…..
7/19/2010
8
I-95 Vehicle Probe Validation
Freeway and arterial travel-times
O-D studies for planning or traffic data
Pedestrian O-D studies (NYC)
Assessment of signal timing on arterials
Urban arterials, DC Demo on July 4th
Freeway Interchange Assessment
Brickyard (Indianapolis) Study
Passenger delay at security check points
Concept is Scale-ableTravel time studies, arterial performance studies, pedestrian O-D studies, cordon studies, and more…
BluFAX Detection Zones
• Class of Bluetooth Radio
Directional antennas
BluFax detects and records signals as they
pass through a detection zone.
Omni-directional antenna
The size and shape of the detection zone
are determined by a combination of:
• Antenna characteristics
• Placement of antenna
BluFAX Sample SizesBluFAX data are a sample. The size of the sample is based on:
Volume Population w/ devices
Station Detection
Matched Pairs
Sample
Station detections are the number of unique IDs captured by a single BluFaxunit during some specified time window.
Matched Pairs are the number of MAC IDs that were detected by pairs of stations during some specified time window.
Volume: Expected traffic volume passing a specific unit.
Population w/ devices. The proportion of the population passing a unit that carry a detectable device.
Volumes and Detection Rates
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BluFAX does not collect traffic volumes, however,
Studies indicate that detection rates track to volumes for comparable time periods.
Proportion of turning movements for arterial intersections and interchanges support this…..
Detections can be compared to volume counts to establish a baseline for a specific location.
Comparison with ATRs
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13
Comparison of BluFAX data with ATR data…..
Speed
Proportion of volume by time of day
Traveltime, Speed, and Delay
Traveltime Difference in time stamp between pairs of units.
Space mean speed . Time it takes to traverse a defined section of roadway.
Speed
Additional travel-time required for a segment.Delay
BluFax uses differences in time and location to measure travel time and speed.
Default distance between units based on straight-line. Can be over-ridden with actual segment length.
Corridor data addresses traveltime or speed along defined corridors.
Can be defined to reflect different entry/exit points along corridors, or to compare alternate corridors.
Arterial Analysis
• Before/After impact of signal timing
• AM, Mid-day, and PM analysis
E
B
C
F
D
A
G
BluFax Measurement Error as a Function of Sensor Spacing and Signal Delay
0.0%
1.0%
2.0%
3.0%
4.0%
5.0%
6.0%
7.0%
200 600 1000 1400 1800 2200 2600
Signal Delay = 20 sec
Signal Delay = 40 sec.
Signal Delay = 60 sec.
Spacing (ft)
Mea
sure
men
t Er
ror
%
Intersections and Interchanges
Turning movement proportions and travel-time (delay) through interchanges, intersections, and roundabouts are measured by placing BluFax units at each approach.
A complex interchange is treated like a small-scale O-D study.
All twelve movements for a complex interchange can be captured with as few as four units.
The key is to ensure that sample sizes on each segment are sufficient for your study needs.
Once units are in place, the additional costs associated with collecting from 1 to 14 days of data are minimal.
I-695 & I-95
INTERCHANGE TURNING MOVEMENTS
BLUETOOTH INSTRUMENTATION
Interchange turning movements
0 6 12 18 24 6 12 18 24 6 12 18 24 6 12 18 24 6 12 18 24 6 12 180
0.5
1
1.5
2
2.5
3
3.5
4Travel Time for segment 6DA-6F3 NB 95 Through
Tra
vel T
ime -
Min
ute
s
Hour of day from 05-Mar-2009 to 11-Mar-2009
Travel Time Data
Outliers
Mean
I-695 and I-95 ALL 12 TURNING MOVEMENTS
FROM I95 NB I95 SB I695 WB I695 EB
I95 NB 5889 3186 520
I95 SB 8039 2895 733
I695 WB 833 543 3817
I695 EB 836 1333 1622
TO
DETECTIONS
BluSTAT Highlights
7/19/2010 20
Data Collection & Processing
• Station Processing– Download data to BluStat– Remove invalid codes – Combine multiple detections – Calculate 5 minute detection rates
• Segment Processing– Define segments (User)– Match pairs, identify outliers– Define filtering parameters– Calculate and graph travel time, speeds– Manually adjust outliers/data points(User)– Output 5, 15 minute, & 1 hour summaries.
Raw data downloaded from BluFax are processed using BluStats.
Record Data Device ID, Sensor location (GPS)
Time, Mac Address
Station Processing
Segment Processing
Record/Store Data
Download
Corridors O-Ds
BluStat outputs KMD files for map display
Detection Data Output
0 3 6 9 12 15 18 21 24 3 6 9 12 15 18 21 240
10
20
30
40
50
60
70
80
90
100
DETECTION RATE PLOT
Station 6FC
Hour of day from 05-Nov-2008 to 06-Nov-2008
Blu
etoo
th d
etec
tions
/ 5
min
5 Minute Detection Rates
0 to 18
0 to 50
0 to 80
0 to 65
Default is straight line distance between units
Marking Outliers and Valid Data Points
Select Data to Mark as outliers or as data
Set maximum and minimum travel time filters.
Segment Plot Results by Day
12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM0
10
20
30
Tra
vel T
ime -
Min
ute
s
TRAVEL TIME :: Segment BE9-D5B Freeway b-c :: 05-Nov-2008
Bluetooth Data
Bluetooth Mean
12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM0
20
40
60
80
100
Speed -
MP
H
SPEED based on a distance of 3.9989 miles
Bluetooth Data
Bluetooth Mean
12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM0
5
10
15
20
25DETECTION RATE
Bluetooth 5 min detection rate
Travel time
Speed
Matched pairs
Segment Data in CSV Format
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Travel times – Urban corridor
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Other Report Options
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30
Once station and segment data are processed, corridor and O-D reports are generated
Corridor and O-D Reports
31
Corridor reports provide summary statistics for linear corridors
O-D generate travel-time and sample size matrices for other non-linear layouts.
O-D Tables
• Method of Aggregation– Process all data
– Filter for date or time.
• Status of Segment– Ok
– Not processed
– No segment
• O-D Data– Number of matched pairs between
defined segments
– O-D data are a sample.
– Can be compared to volume data.
32
Origin-Destination Reporting Parameters
METHOD ALL
Status of O-D Pairs
END STATION
BEGIN STATIONUNIT A UNIT B UNIT C
UNIT A OK OK OK
UNIT B OK OK OK
UNIT C OK OK OK
O-D Data
END STATION
BEGIN STATIONUNIT A UNIT B UNIT C
UNIT A 14329 9088 4618
UNIT B 7877 4618 297
UNIT C 5040 310 2418
O-D reports are generated for pairs of stations defined by the user.
Date and Time Filters
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Origin-Destination Reporting Parameters
METHOD DATE_TIME_FILTERED
DATETIME BEGIN
DATETIME END
SEARTCHTIME MINIMUM 0:00:00
SEARCHTIME MAXIMUM 3:00:00
Status of O-D Pairs
END STATION
BEGIN STATION UNIT A UNIT B UNIT C
UNIT A OK OK OK
UNIT B OK OK OK
UNIT C OK OK OK
O-D Data
END STATION
BEGIN STATION UNIT A UNIT B UNIT C
UNIT A 4273 4293 2132
UNIT B 3652 1081 82
UNIT C 2375 96 705
11/5/2008 0:00
11/5/2008 23:59
Date_Time filter settings depend on purpose of study.
Segment with the same beginning and end point, and longer time window, provides O-D information for vehicles entering and leaving via the same route.
BluFax CharacteristicsThe same basic principles apply to most study types, however the detailed design of the study and strategies for data analysis are tailored to the situation.
The majority of detectable devices are carried by an individual who may be on foot, in an automobile, truck, bus, or the local coffee shop; or vehicles in main lanes and adjacent HOV lanes.
BluFax picks ups all signals within its detection zone
Can pick up multi-modal trips
Can follow specific signals over series of segments.
Resources Available
• Technical Guides
– BluFax Specifications Sheet
– BluFax Operators Manual
– BluStat Operators Manual
Traffax Staff are available to discuss approaches to studies and analysis processes.
• Technical Notes
– Application Areas
– Specific considerations
– Lessons learned
Please contact Donna Nelson ([email protected]) if you would like personalized, on-line webinars or tutorials.
Technical Information
Traffax senior technical staff are all experienced transportation and traffic professionals. We are committed to helping you and your customers effectively use our equipment for your projects.
• Discuss your needs associated with specific RFPs/projects.
• Provide information to support your proposals and work plans.
• Help you address and answer your client’s questions about the hardware, software or applications.
• Provide personalized on-line tutorials to help you get started with BluFax.
