Carbon Footprint of the U.S. Population: Causes and Spatial-Temporal Pattern: Vehicle Occupancy Midterm Report Class Project Me/ENV 449, 2007 Timothy Arde-Acquah, Louis Hsu, and Jason Link Instructor: R. Husar

Introduction Purpose –Find vehicle occupancy data (passengers per vehicle) for years , separated by state and vehicle type, if possible Approach –Searched numerous websites Major Finding –Overall, the most complete set of data was a nationwide compilation spanning from

Results (Timothy)  Introductory - Working Definition: "Vehicle occupancy conceptualized as function of number of people in the vehicle and distance traveled per trip." - 5 Vehicle Occupancy Measurement methods: traditional roadside/windshield observation, carousel observation, photographic surveillance, mail-out or telephone surveys, accident database extraction method.

Results Secondary - Daily Passenger Travel Fig.1-Passenger Mode of TravelFig.2- Mean Occupants by Trip Purpose SOURCE: The 2001 National Household Travel Survey, person file, U.S. Department of Transportation. SOURCE: The 2001 National Household Travel Survey, person file, U.S. Department of Transportation.

Results/Findings Passenger-Vehicle Occupancy (Sample findings) Per seven county area within the US: * 71.5% of all vehicle trips are made in single-occupant vehicles. *The average passenger-vehicle occupancy for all trip purposes is *The passenger-vehicle occupancy for Home Based Work trips is NOTE: Passenger-vehicle occupancy was calculated by dividing the sum of all passengers (that is, the sum of the modes “Drove Alone,” “Drove with Passenger” and “Rode as Passenger”) by all passenger vehicles (that is, the sum of “Drove Alone” and “Drove with Passenger.”) -Vehicle Occupancy per Vehicle Mile by Time of Day and Weekend Status (Tables available on Class wiki) -Probably useful: How to calculate AVO rates

Results (Jason) Nationwide Personal Transportation Survey (NPTS) –1969 –1977 –1983 –1990 –US DOT –FHA Trip Purpose, Trip Length, Household Size, Place of Residence

Vehicle Occupancy by Trip Purpose (1977)

Comparison of Vehicle Occupancies

National Vehicle Occupancy Rates- BTS (Louis) Source:

Cross Checking Data NPTS vehicle occupancy rates cross-checked with BTS data shows that they are similar NPTSBTS averageBTS passenger carBTS other 2 axle, 4 wheel

Further Research Crosscheck state and national vehicle occupancy rates to see if they are similar If similar, national data is satisfactory If not, find comprehensive vehicle occupancy data from , broken down by –State –Vehicle type