310 likes | 492 Views
Tracking Bluetooth IDs To Measure Travel Time & Origin/Destination How does it work? What information does it give?. With California law requiring hands free cell phone use, we see less of this. And more hands free cell phone use like this.
E N D
Tracking Bluetooth IDs To Measure Travel Time & Origin/Destination How does it work? What information does it give?
With California law requiring hands free cell phone use, we see less of this . . .
These ‘hands free’ devices use Bluetooth communications • Bluetooth operates in 2.4 GHz ISM radio band • Each Bluetooth device has an unique 48 bit ‘MAC’ address • There are 3 Bluetooth device classes based on emitted power • Class 1 up to 100 mW, range up to 100 meters • Class 2 up to 2.5 mW, range up to 22 meters • Class 3 up to 1 mW, range up to 6 meters
These ‘hands free’ devices use Bluetooth communications • Bluetooth operates in 2.4 GHz ISM radio band • Each Bluetooth device has an unique 48 bit ‘MAC’ address • There are 3 Bluetooth device classes based on emitted power • Class 1 up to 100 mW, range up to 100 meters • Class 2 up to 2.5 mW, range up to 22 meters • Class 3 up to 1 mW, range up to 6 meters High gain antennas can extend the range at which these devices are ‘read’ when they are discoverable
Bluetooth IDs can be read from vehicles 300 feet away Including those on roadways which may not be of interest
Shielding can limit reception to the area of interest This roadway area will be ignored
How are Bluetooth IDsRead? Electronics in a weatherproof case at roadside sends out an inquiry to Bluetooth devices in the vicinity every few seconds . . . .
Bluetooth devices nearby respond with their IDs which are recorded with date and time GPS Date GPS Time # of reads Bluetooth ID (hex) Bluetooth ID (decimal) Dwell Time At Site Non-reversible encryption can be done by erasing 1 bit in each Bluetooth ID
Even on urban and suburban streets, many Bluetooth IDs will be read Over 11,000 IDs were read in 4 days on a small arterial
Bluetooth IDs + GPS time measure travel time directly Data record when ID passed first BluFax Data record when ID passed second BluFax Travel time for this Bluetooth ID The travel time is the difference in GPS times
The travel times are a mix of uninterrupted + interrupted trips Interrupted Trips Uninterrupted Trips Only uninterrupted trips characterize traffic system performance
Identifying the Uninterrupted Trips Is Easy Interrupted Trips The interrupted trips are all those travelers who stopped to shop, get gas, visit the bank - - - extending their trip time arbitrarily.
What Can We Do With BluFax? • Measure travel time along a corridor • BluFax at beginning, end, and key entry/exit points • Confirm benefits of signal coordination • Measure origin and destination of travelers • Requires BluFax at all boundary entry/exit points • Measure delay on approaches to a signal • BluFax on each approach ~200’ back from stop line • Identify causes for congestion • Identify influence of traffic management on travel demand
Some Examples of Actual Usage • Temecula: confirm signal coordination benefits • Murrieta: confirm signal coordination benefits • Pleasanton: track cut-through traffic from freeways • CCIT: measure travel times on urban streets • PATH: measure travel times on freeways • Omni-Means: origin/destination in downtown Napa • Quality Traffic Data: corridor travel time in Walnut Creek • Stantec: origin/destination on freeways for SANDAG • DKS: origin/destination + travel time on freeways for RCTC
A Specific Example: Origin/Destination + Travel Time on the 91 Freeway Each pushpin symbol was a BluFax unit A total of 13 BluFax units were deployed
Typical Site Mounted BluFax on an Existing Pole A B BluFax at site A read 60% of IDs read by a BluFax at site B Both directions on most freeways can be monitored with 1 unit
A simplified diagram of measurements For just one movement of traffic
Here are some of the results found for one 3 hour time period
Here is the 6AM Caltrans Traffic Map from IE511 Traffic from 71 Southbound enters the 91 Westbound and congestion spills back Eastward
BluFax – the tool used for data collection • A portable unit in a weatherproof case • Internal GPS for location + precise time • Internal GSM modem for data communications • Can send email with data collected each day • Can operate as a real time unit also • Battery provides up to 2 weeks of operation • 2 GB memory stores all data collected • BluFax can be purchased or rented • BluStats PC software included (batch software) • Processes data into charts • Exports data to EXCEL • Very is easy to use • Windows 7 or XP compatible
Real Time Usage • This is the next step after using BluFax as a “study tool” • Firmware allows any BluFax to do real time monitoring • Server is required to receive and process the data • BluFaxWeb is available as a rental service on Traffax’ server • BluFaxWeb software is available as licensed software on user’s server • Either way, results are delivered as an XML feed • Requires a communication network to all BluFax sites • Data security is a solvable challenge • BluFax can encrypt Bluetooth MAC IDs as they are read • The encryption used is non-reversible (and simple) • Traffax has real time systems in place in US & Australia
Where are we going? • Fostering acceptance of new technology • Engineers learn it in school and carry concept into employment • Researchers use it and develop applications practices • Practicing engineers learn about it in projects • We have moved beyond the technology • Implement user applications • Provide accurate travel time information • Measure origin/destination movements • Measure movements along a corridor • Focus on user needs (financial and technical) • Rent equipment allow low cost evaluations and study projects • Rent server/software to facilitate transition to real time It takes 10+ years for new technology to be widely accepted
BluFax makes travel time and traveler origin/destination directly observable On Freeways . . . as well as Arterial Streets Making it easy to show stakeholders the value of improvements
Further information is available at www.traffaxinc.com Traffax, Inc. is the manufacturer of BluFax Or, feel free to contact: Mike Juha mikejuha@gmail.com Tel: 951-600-9499 Cell: 949-310-5106