july 4 blufax demo briefing

Demonstration of Bluetooth-based Traffic Monitoring Technology

Demonstration Results 4th of July Weekend 2009

Prepared for:District of Columbia Department of Transportation

Donna C. Nelson, PhDTransportation Perspectives [email protected]

Stan Young, PhDTraffax [email protected]

Acknowledgements

Traffax, Inc

This demonstration was conducted as a collaborative effort by:

Transportation Perspectives, Inc

District of Columbia Department of Transportation

University of Maryland

Transportation Perspectives [email protected]

Presentation

Background/overview Purpose and objectives of the test Overview of Blu-FAX Technology (the basics) Study Approach (what we did) Presentation of Test Results Lessons Learned Applications of BluFAX for a wide-scale test Additional applications of BluFAX


Background

The 4th of July celebrations present a unique opportunity to collect data to test and refine traffic management strategies. Evacuation routes and strategies Signal timing and traffic management strategies Special events planning and management.


Background

Do not provide sufficient data to support DDOT analysis and modeling needs.

Travel time runs (floating car techniques) yield limited data on congested roadways.

Cost of traditional data collection approaches is labor intensive and expensive.

Data collection efforts limited to 9:00PM to 12:00 AM on July 4.


Traditional Traffic Studies

Background

Providing real-time freeway travel time data Evaluation of Signal Timing Improvements along arterial roadways. Monitoring pedestrian and vehicle traffic at Indianapolis Speedway (The

Brick Yard) Events. Estimating passenger delay at airport security check points

BluFAX has performed well for a variety of applications that are similar to those needed to support Operation Fast Forward. Examples include:

These studies suggest that BluFAX is suitable for use in the Capital Mall area, however the technology has not yet been tested in a dense, urban environment.


Demonstration Objectives

Use in dense urban environments Extremely heavy pedestrian volumes Pedestrian travel speeds that may be higher than vehicle speeds at times Roadway environment and security considerations dictate available locations

of data collection units.

Technology Filtering approaches (BluStat Software) developed for freeway and/or

higher-speed arterial roadways may require adjustment for application. Addressing bi-modal distributions among pedestrian and vehicle traffic Antenna footprint /or other factors related to detection rates.

A demonstration on the 4th of July is an opportunity to assess the capabilities and performance of BluFAX


Demonstration Objectives

Obtain Data set to support evaluation of BluFAX processes and performance Detection rates and matched detections along study corridor. Familiarization with BluFAX data processing features and capabilities. Organization and format of BluStat output. .

Define and assess potential for BluFAX use BluFAX capabilities and applications as part of comprehensive data

collection efforts. Potential use in a multi-corridor data collection effort on the 4th of July Additional applications of interest to DDOT, that build on BluFAX

capabilities. Consider strategies/options for locating portable as well as permanently

installed units.


BluFAX Technology

Overview of capabilities and features


BluFax Technology

10

2 miles

Traffax Equipment**

* Bluetooth signals come from cell phones, PDAs, laptops, GPS, car radios…** Provisional patent received

BluetoothSignal *

Time = 8:03:26 AM

Time = 8:05:58 AM

Travel Time = 2:32 MinutesSpeed = 51.7 MPH

How it works


Detection Zone

A BL = Length of segment

Detection Zones

A Bluetooth enabled device may be detected more than once as it passes through a detection zone.

As traffic slows, the probability of getting multiple observation of the same MAC ID from a single device increases.

BluFAX detects and records Mac addresses present within the detection zone.

Size of detection zone depends on antenna strength, placement of units, and other factors related to the environment.

Processing software configured to detect and address multiple detections.


BluFAX Capabilities

Ability to collect data continuously over an extended period of time. BluStat software processes raw data and delivers output in graphic and

tablular formats (CSV and Excel). Substantially lower labor costs associated with conducting travel time studies

and manual turning movement counts. Can be deployed to obtain information not available by other means:

Time-based origin-destination data for both pedestrians and vehicles. Direct measures of travel time and delay along routes.

Technology minimizes concerns related to public privacy.

Key features of BluFAX

Additional information available at www. Traffaxinc.com


Demonstration Details

4th of July Demonstration


Details-Study Area

7th and Indiana Ave 7th and F Street 7th and K Street 7th and S Street

Four (4) BluFAX units were placed along the Georgia Avenue/7th Street Corridor

Units collected data continuously from approximately

7PM, Thursday, July 2 7AM, Sunday, July 5


Details-Placement of Sensors

Vehicles were placed on side streets, generally within 50 feet of the intersection of interest. Closest parking space to intersection was reserved by DDOT for study. Portable units placed on floor of vehicle and covered. Antenna affixed to window of vehicle using adhesive fasteners. Location of antenna provided a clear view of intersection Demo employed Class I antennae with a rated open air range of 100 m. Detection during demo limited by line of site obstructions (buildings and

other structures)


Sensor Locations Adjacent to 7th Street

Indiana Avenue, NW

One-way traffic

Metro Entrance

Sensor Location

F Street, NW

Sensor Locations Adjacent to 7th Street

K Street S Street

Sensor Location

Sensor Location


Data Format and Processing


Data Collection & Processing

Station Processing Invalid codes Multiple detections combined 5 minute detection rates

Segment Processing Matched pairs Filter outliers and data points Calculate travel time, speed Output 5, 15 minute, & 1 hour

At the end of the study, raw data were downloaded and processed using BluSTAT software provided with the equipment.

Data Recorded Device ID Sensor location (GPS) Time Mac Address

Station Processing

Segment Processing

Data Recorded


Station Analysis

Detections include all valid IDs recorded within the detection zone. The software discards invalid MAC IDs. Identifies and addresses multiple detections from the same ID Multiple detections within a 4 minute threshold are treated as a single

detection. Detections that are separated by a larger time gap are treated as separate

detections.

Data stored on memory media from each unit are downloaded to a PC.

Study Detection Rates 2nd – 5th July

5 Minute Detection Rates General patterns similar for all stations. 5 Min. rates at Indiana Ave, F St, and K St range from 10

to 60 per 5 minute period between 9AM and 12AM. Detections at S St much lower but could be due to

differences in cross-street traffic and pedestrian traffic.

Detections include all valid IDs recorded within the detection

zone. Invalid MAC IDs discarded. Multiple detections from the same ID w/in 4

minute threshold treated as one detection Detections > min apart treated as separate

detections.


Study Detection Rates 2nd – 5th July

Spike in traffic due to exodus from fireworks display is shown at all stations.

Segment Processing

Segments are defined in the BluFAX Software Detection records from two sensors are compared to identify “matched”

pairs. Direction of travel is determined based on the order in which IDs are

recorded (based on segment definitions_ Station A to Station B Station B to Station A

Sensors use GPS coordinates to determine straight-line distance between units, time references for sensor units are synchronized.

Once Station and Segment data are processed, segments can be defined as a “corridor”.

Travel time and speed data are determined by matching detection records from two sensors.


15 Minute/1 Hour Segment Reports

15 minute and 1 hour summary reports By travel direction and study date Number of good data points on segment represents matched pairs, which

also indicates sample size Travel time summaries for section/time period.

BluStat exports data in CSV and Excel formats based on filtered data.

Excel Output Format for 15 minute and 1 hour summaries

Summary Statistics for 15 minute periods


Travel Time Plots

182124 3 6 9 1215182124 3 6 9 1215182124 3 6 9 120

5

10

15

20

25

30

Tra

vel T

ime

- M

inut

es

Travel Time DataOutliersMean

X

BluStat Output

BluStat identifies “outliers”, which are not used to calculate travel time.

Classifications can be changed manually. Select individual points Minimum/maximum travel times

Currently, criteria for identifying outliers are set for freeways/arterials

Criteria for high-density environments likely to be different


Segment Processing

182124 3 6 9 1215182124 3 6 9 1215182124 3 6 9 120

5

10

15

20

25

30

Tra

vel T

ime

- M

inut

es

These results have not been confirmed through statistical analysis!.

BluFAX plots a mean travel time based on all data points.

Once that line is removed, the data points appear to group into three categories based on travel times:

2 to 3 minutes

5 to 15 minutes

> 15 minutes


Traffic passing through study intersections on cross streets

Pedestrians entering metro at or between sensor locations.

Vehicles turning off or onto segment between sensors.

Sample size is the number of matched pairs between two stations.

The number of matches can be reduced by

Intersections marked with blue circles are locations where 2008 data indicate points where vehicles could enter or exit route between sensors.

Sensors can be placed at intersections or mid-block.

Matching Pair and Sample Sizes


Building on time/location data

Sensors record the time and location a specific ID is identified.

Segments can be defined between stations for different purposes.

A series of segments can be defined as a corridor to estimate through that corridor, but depending on how links are defined, may not reflect travel times on a specific roadway segment. .

Travel time data will be based on the shortest distance between the two stations that form a segment.

Time and location matches can be used to provide O-D data and/or derive turning movements.


Summary

The BluFAX performed well for collection of travel time data along 7th Street on the 4th of July Capable of collecting high-quality data over a period of several days. Units

were checked during the study period, however no problems were encountered.

Placement and monitoring BluFAX units for the demonstration involved four field staff and a supervisor for approximately 10 hours total to place, monitor, and retrieve sensor units and to download data from sensor units. Time requirements per unit should be less for larger-scale studies.

The demonstration did not specifically address the use of BluFAX to collect pedestrian data, however, this capability could provide an added dimension to DDOTs ability to manage and monitor vehicle and pedestrian travel times.


Summary

BluStat software processes and packages data in graphic and tabular formats.

Tabular data is comparable with formats used for traditional traffic studies. Data can be exported to CVS and Excel formats for further analysis. It should be feasible to develop approaches to data analysis to address

issues related to high pedestrian volumes and congested roadway conditions following special events.

Developing a study design that addresses vehicles turning off the study corridor at key routes between sensor units should increase. Data from 2008 suggest that 22% of vehicles turn right onto New York

Avenue alone. . A thorough analysis of 2008 study data along the corridor may provide

more robust estimates of how turning movements impact matched pairs on some roadway segments.

Data Processing and Analysis


Study Design Considerations

The output provided by BluFAX is a sample and cannot provide traffic volumes or classification counts. Other studies indicate that sampling rate for specific locations remains somewhat constant over time.

Volume counts may be needed at some locations, to provide a basis for estimating volumes.

Placement of units in subsequent studies should allow demonstration of O-D capabilities.

A study design that builds on BluFAX capabilities may be able to fully or partially replace manual turning movement counts.

Study Design Considerations


Summary

Location in vehicles worked well for this study, but is not appropriate for all situations (such as along Constitution Avenue)

Sensors locations Advance lead time is needed to identify candidate locations Units may be placed in vehicles or secured to the

infrastructure Mounting brackets needed to allow portable units to be

mounted above ground level, to poles or elevated structures. DDOT should consider permanent installations at some

locations that support on-going use for a range of applications, supplemented by portable units for short-term, special studies.

Securing Units


For Information

Donna Nelson, PhD. [email protected] www.t-perspectives.com

Stan Young, PhD [email protected] www.traffaxinc.com


mailto:[email protected]

july 4 blufax demo briefing

Documents

limited data

data set

sufficient data

phdtransportation perspectives

data collection efforts

blufax useblu

evaluation of blufax

monitoring pedestrian