Washington University Transportation Emission

• Commuter– Faculty/Staff– Students

• University Fleet

• Air travel– Athletic Meets – Study Abroad

Emission Calculation for Commuter Transportation

• Factors effecting the emission:– # of people commuting to WashU– miles driven per year– gallons of fuel required– amount of Carbon or Carbon Dioxide produced by the fuel

FuelofGallon

gmCarbon

Miles

FuelofGallons

Year

MilesPersonEmission

__

)(__#

miles gallons2,421 grams of Carbon/Gallon as given by the Code

of Federal Regulations (40 CFR

600.113)

0.99 % fuel

oxidized 12 gm C

44 gm CO2

mileyearEmissions X= XXXX# people

Data Collected

• Student Parking Permit Data: Only 2007-08.

• Student Local Address Data

• Student Home Address Data

• Faculty/Staff Parking Permit Data: Only 2007-08.

• Faculty/Staff Local Address Zip code: Only 2007-08.

Issues with Data

• Some students provide their permanent home address zip code instead of local address zip code

• Each year over 3000-4000 students do not provide zip code.

• Historic parking permit data not available.

• Historic faculty/staff local zip code not available.

Distance Calculation

• Zip code converted to latitude and longitude based on U.S. Gazetteer and zipinfo.

• For WashU, coordinates of Brookings Hall (38.648N, 90.305W) considered.

• Distance from zip code coordinates to WashU coordinates calculated using the reference formula: – Δx = 69.1*(lat1-lat2); Δy = 53.0*(lon1-lon2), – Distance (in miles) = (Δx2+Δy2) 1/2.

• Calculates straight line distance between WashU and centroid of zip code

• Distance within 150 miles to WashU considered for analysis.

• Fudge factors required for calculated distance– Highways and road directions– Bridges on East and North St. Louis

• 18% for Students • 40% for Faculty/Staff

Annual Distance Traveled

• Assume every person makes 1 round trip (2 trips) to school per working day of the year

• Faculty/Staff - 225 working days per year

• Students - 165 working days (excluding vacations)

Fuel Economy for Carbon Emissions Calculations

• Gallons per mile based on EPA report: Light Duty Automotive Technology and Fuel Economy Trends: 1975-2007

• Estimations based on– stop-and-go city driving– 43% city and 57% highway weighted averages– three-year moving averages– sales fractions of cars and light trucks

• Fuel economies based on EPA fuel economy database

As students moved closer to campus, number of parking permits issued decreased.

Annual miles driven per student decreased most dramatically from 2002-2007. This is explained in part by the shift in student residences from 2001-2007.

1991-92

1995-96

2000-2001

2007-08

Total miles traveled by students correlates with number of permits issued.

Fuel economy improved until 1999 when sales fraction of SUVs increased.

Gallons of gasoline consumed decreased with decreasing distance traveled.

Student Carbon Emissions, and Driving Factors

Confidence intervals in miles driven annually per student

Student Commuter Carbon Emissions

University Fleet Contribution

The University fleet grew and contribution steadily increased despite improvements in fuel economy, yet is minimal in comparison to student commuter carbon emissions.

Air Travel Emissions

• General areas of air travel– Faculty– Study abroad– Athletics

• Methodology– Faculty air travel not considered – Study abroad data was provided for the past 6

years– Athletic air travel data provided for the past 3

years

• Air travel emissions have increased by 30%

• Air travel emissions are the driver in this study

Upper Bound Transportation Emission

Lower Bound Transportation Emission

Washington University Transportation Emission