Air Quality and Multimodal Evaluation of an Adaptive Traffic Signal System: a case study on Powell Boulevard (Portland, Oregon) Courtney Slavin Dr. Miguel Figliozzi Western District ITE Conference Santa Barbara, CA Tuesday, June 26 th, 2012

Outline Objective Air Pollution Powell Boulevard Background Adaptive Traffic Signal Control Data Collection Analysis Conclusions Future Work 2

Objective Is air quality affected by traffic signal timing? What factors are significantly contributing to air pollution? 3

Air Pollution Regulated by US EPA (Environmental Protection Agency) NAAQS (National Ambient Air Quality Standards) – Carbon monoxide – Particulate matter – Nitrogen oxide – Sulfur oxide – Smog – Lead 4

Carbon Monoxide (CO) From incomplete combustion of fuel Reduces amount of oxygen to the body Health effects: visual impairment, headaches, reduced work capacity (EPA) 5

Particulate Matter (PM) Vallero, D. Fundamentals of air pollution. Academic press, Made up of acids, organic chemicals, metals, and soil or dust particles PM 2.5 particles ≤ 2.5 µm in diameter Regulated Ultrafine particles (UFP) ≤ 0.1 µm in diameter Not regulated Smaller sizes travel deeper into lungs Health effects: asthma, respiratory infections, cardiovascular disease, chronic bronchitis

Powell Blvd. Background Urban commuter arterial in Portland, Oregon Connects Portland downtown to Gresham High frequency bus route 7

Traffic Volumes 8 Peak Hour – Westbound: 1,500 vehicles (7-8 am) – Eastbound: 1,800 vehicles (4-5 pm) Daily – Westbound: 19,000 – 22,000 vehicles – Eastbound: 18,000 – 20,000 vehicles – Total: 40,000 vehicles

Adaptive Traffic Signal Control The City of Portland implemented an adaptive traffic signal system along Powell Boulevard on October 8 th, 2011 SCATS: Sydney Coordinated Adaptive Traffic System Developed in Australia SCATS adjusts cycle length, phase splits, and offsets to optimize traffic Maintains the highest acceptable degree of saturation 9

Data Collection Powell Blvd. & 26 th Avenue 10

Data Collection 11 Wednesday, October 26 th, 2011 Morning (7-9 am) peak period Equipment location: – 3’ from side of bus shelter – 12’ from curb – 5’ height for tubing Bus and heavy vehicle presence

Data Collection Setup 12 Powell Blvd. 26 th Ave. Bus Shelter West P-Trak: UFP Dust Trak: PM 2.5 Langan: CO Hobo Data Logger: Temperature, Humidity NE Corner Anemometer: Wind Speed & Direction NW Corner SW CornerSE Corner

Traffic Signal Timing Data Before SCATS: Time of day plans After SCATS: Adaptive timing plans – Detector volumes – Phase timing (start and end time times) – Cycle length 13

Phasing Diagram Powell Blvd. 26 th Ave Bus Shelter 1 5 Phase(s)Movements A 2 & 6WBTH & EBTH C 2 & 5WBTH & WBLT E 1 & 6EBTH & EBLT F 1 & 5EBLT & WBLT D 4NBTH & SBTH 14 3 left turn options depending on demand

Analysis 15 Phasing descriptive statistics Cycle length comparison – Adaptive vs. Time of Day Regression analysis – Which of the following factors are significant in explaining pollutant levels (UFP, PM 2.5 & CO)? Traffic signal timing parameters Traffic volumes Heavy vehicles Transit buses

Phasing Descriptive Statistics (in seconds) 16 MinMedianMean Standard Deviation MaxFrequencyTOD Phase A Phase C Phase E Phase F Phase D Cycle Length

Adaptive vs. Time of Day Cycle Length 17

Regression Analysis Results – PM Parameter % Change per Unit Change in X % Change per 1% Change in X % Mean Contribution* Bus Red Light (secs) Heavy Vehicle Presence (1 or 0) Green A (secs) Green E (secs) Green D (secs) Volume/Cycle (vehs) *Relative to baseline (sum of constant, temperature, and relative humidity For example: 1 extra second of green time for Phase A reduces PM 2.5 by 0.28%.

Conclusions 19 Longer green time on Powell reduces air pollution Relative to the baseline atmospheric conditions, the largest mean contributions to in PM 2.5 are: – Green A: 19% reduction – Green D: 8% increase – Volume: 7% increase – Heavy vehicles and bus presence are < 1%

Future Work Include CO 2 Analysis at other two corners of the intersection 20

Acknowledgements Oregon Transportation, Research and Education Consortium (OTREC) Peter Koonce & Willie Rotich (City of Portland Transportation Bureau) David Crout & Kurtis McCoy (TriMet) Eric Albright (Portland State University) 21

Questions? 22 Courtney Slavin Graduate Student and Research Assistant, ITS LAB Department of Civil & Environmental Engineering Portland State University Phone: Miguel Figliozzi Associate Professor Department of Civil & Environmental Engineering Portland State University P.O. Box 751 Portland, OR Phone:

References Particulate Matter: Air & Radiation. Six Common Air Pollutants. [Online] US EPA. [Cited: July 2, 2011.] Vallero, D. Fundamentals of air pollution. Academic press, Particulate Matter: Air & Radiation. Basic Information. [Online] US EPA. [Cited: July 2, 2011.] 23

Regression Analysis Results – UFP 24 Parameter % Change per Unit Change in X % Change per 1% Change in X % Mean Contribution* Bus Red Light (secs) Green A (secs) Green C (secs) Volume/Cycle (vehs) *Relative to baseline (sum of constant, temperature, and relative humidity

Regression Analysis Results – CO 25 Parameter % Change per Unit Change in X % Change per 1% Change in X % Mean Contribution* Diesel Particulate Filter on Bus (1 or 0) Heavy Vehicle Presence (1 or 0) Green A (secs) Green F (secs) Green C (secs) Cycle Length (secs) Volume/Cycle (vehs) *Relative to baseline (sum of constant, temperature, and relative humidity