# Presentation: 502464

## Vehicle Energy Use

- Mark Schipper
- Energy Information Administration
- American Statistical Association
- Committee on Energy Statistics
- October 20, 2005

## Acknowledgements

- Federal Highway Administration, U.S.DOT
- National Highway Traffic Safety Administration, U.S. DOT
- Bureau of Transportation Statistics
- Oak Ridge National Laboratory, Center for Transportation Analysis, U.S. Department of Energy (ORNL)

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## Energy Use by End-Use Sector

- Transportation

- Industrial

- Commercial

- Residential

- Transportation sector use of energy experienced tremendous growth overall, but registered noticeable pauses in 1974, 1979-1982, 1990 and 1991, and 2001. In 2004, petroleum accounted for 97 percent of the sector’s energy, and motor gasoline accounted for two-thirds of all petroleum used in the sector.

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## Why were we interested?

- EIA’s Surveys on the Demand-Side of the Energy Equation –  Residential Buildings, Manufacturing Plants, Commercial Buildings
- Residential Transportation (known as RTECS) was conducted in 1983, 1985, 1988, 1991, and 1994 then discontinued
- Investigate using *2001 National Household Travel Survey *as a replacement for discontinued data series; next release NPTS 2008 (?)

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## What we did – Augmented NHTS

- Vehicle-Level Data
- Fuel Economy (mpg)
- Fuel Type
- Energy Consumption (equivalent gallon)
- Energy Price (cents per equivalent gallon)
- Energy Cost ($ per year)
- Energy Consumption
- EIA “On-Road, In-Use” mpg-1 x vmt

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## Data Sources

- Fuel Economy
- NHTSA Corporate Average Fuel Economy program
- EIA data/experts on pre-78 model years
- Fuel Prices (month by state)
- EIA Monthly Supplier Surveys
- Form EIA-782A, “Refiners’/Gas Plant Operators’ Monthly Petroleum Product Sales report,” and
- Form EIA-782B, “Resellers’/Retailers’ Monthly Petroleum Product Sales Report”
- Federal, State and Local Excise Taxes (FHWA)

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## Schema for Estimating Energy and Energy-Related Statistics, 2001

- From NHTS/EIA:
- Vehicle-Miles
- Traveled (VMT)

- From EPA/NHTSA:
- Fuel Economy (MPG)

- From EIA:
- Retail Fuel Price
- (DPG)

- Merge

- 1) Select Vehicle
- 2) Adjust Fuel Economy to On-road, In-use Values

- Merge

- Vehicle Fuel Consumption:
- =VMT During Possession/MPG

- Vehicle Fuel Expenditures:
- =DPG*Gallons

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## Linking: 1 to Many

**Volkswagen, Jetta, 2001, Auto, ****??.?**

**Volkswagen, Jetta, 2001, Auto, ****44.8**
**Volkswagen, Jetta, 2001, Auto, ****26.3**
**Volkswagen, Jetta, 2001, Auto, ****52.6**
**Volkswagen, Jetta, 2001, Auto, ****29.4**
**Volkswagen, Jetta, 2001, Auto, ****29.2**
**Volkswagen, Jetta, 2001, Auto, ****25.1**
**Volkswagen, Jetta, 2001, Auto, ****31.7**
**Volkswagen, Jetta, 2001, Auto, ****31.4**
**Volkswagen, Jetta, 2001, Auto, ****31.3**
**Volkswagen, Jetta, 2001, Auto, ****29.5**
**Source: NHTSA, CAFE Program A. Berkowitz.**

**MPG 45/55**

**Select One**

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## Linking Results

| Number of Eligible Donor Vehicles | Number of Vehicles in NHTS Sample |
| --- | --- |
| 1 | 5,238 |
| 2 to 5 | 19,617 |
| 6 to 10 | 11,225 |
| 11 to 20 | 5,399 |
| 21 to 30 | 1,273 |
| 31 to 40 | 1,148 |
| 41 to 50 | 1,672 |
| 51 or more | 2,127 |
| Total | 47,699 |

- Presumed Imputation Quality

- Low

- High

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## Adjusted Fuel Economy

- On-Road, In-Use Fuel Economies Differ from EPA’s Unadjusted 45/55 Combined Estimates
- Adjust for On-Road Shortfall (Hellman and Murrell, 1985)
- Adjust for In-Use (Crawford, 1983)
- Details www.eia.doe.gov/emeu/rtecs/nhts_survey/2001/index.html
- Verified in 1991 and 1994 RTECS

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## Adjustment Equations for Vehicle i in Month j

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## Example of MPG Adjustments (Composite MPG = 25.1)

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## Sensitivity Analysis and Guidance

- Various Selection Routes versus Single Value Selection
- Sales-Weighted Value of Fuel Economy
- Lowered Consumption by 2 percent
- Maximum Fuel Economy – 95th Percentile
- Lowered Consumption by 9 percent
- Minimum Fuel Economy – 5th Percentile
- Raised Consumption by 7 percent
- Given these bounds, along with survey sampling and non-sampling errors, the use and usefulness of an enhanced NHTS should be evaluated against a researcher’s project requirements. (Author’s Note)
- Interactive Tables for Data Quality, based on (1) Sample Counts and (2) Measures of Precision

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## Working with NPTS 2008

- Verification of EIA’s Adjustments (unlikely)
- Fuel purchase and travel diaries
- Minimize Imputation Errors (likely)
- Collect additional vehicle characteristics – type of fuel, price paid for fuel, number of cylinders, Vehicle Identification Number (VIN) for more characteristics data
- Capture Vehicle Disposition Data (likely)
- CIPSEA ensures confidentiality and the enhanced ability to share data among some agencies (done)

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## Questions for the Committee

- Do the extensive assumptions in creating this data set cause any concern about this as an official EIA data release
- Should EIA expend resources to do this again with the NPTS 2008
- If so, should EIA establish any ground rules with U.S. DOT before undertaking such work
- Improvements? Data, Methods, and so on.

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## Thank you kindly for your time and attention

- Contact:
- Mark Schipper (202.586.1136)
- _[mark.schipper@eia.doe.gov](mailto:mark.schipper@eia.doe.gov)_

## EPA Testing Protocols

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## More EPA Testing Protocols

- The "city" program is designed to replicate an urban rush-hour driving experience in which the vehicle is started with the engine cold and is driven in stop-and-go traffic with frequent idling. The car or truck is driven for 11 miles and makes 23 stops over the course of 31 minutes, with an average speed of 20 mph and a top speed of 56 mph.
- The "highway" program, on the other hand, is created to emulate rural and interstate freeway driving with a warmed-up engine, making no stops (both of which ensure maximum fuel economy). The vehicle is driven for 10 miles over a period of 12.5 minutes with an average speed of 48 mph and a top speed of 60 mph.
- Both tests are performed with the vehicle's air conditioning and other accessories are turned off.

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