Eco-driving: Strategic, Tactical, and Operational Decisions of the Driver that Influence Vehicle Fuel Economy Brandon Schoettle Project Manager Sustainable Worldwide Transportation
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Sustainable Worldwide Transportation Research on energy, environmental, and safety aspects of future road transportation worldwide
Eco-Driving: Strategic, tactical, and operational decisions of the driver that influence vehicle fuel economy Michael Sivak Brandon Schoettle Report No. UMTRI-2011-34 Transport Policy, 2012, vol. 22, pp. 96-99 * Updated through model year 2014 *
On-road fuel economy: 1923-2008 +3.4 mpg
Travel mode BTU per occupant mile Other light-duty vehicle 3,980 Car 3,501 Airplane 2,931 Transit bus 2,656 AMTRAK 1,745 Motorcycle 1,742
Driver decisions Strategic Tactical Operational
Level Factor Effect (MY2014) Strategic Vehicle class 45% Vehicle model Vehicle configuration 933% all cars 400% cars excluding EVs 485% all SUVs 138% SUVs excluding EVs 109% all pickups 29% cars, 59% pickups Out-of-tune engine 4-40% Tires with 25% higher rolling resistance 3-5% Tires underinflated by 5 psi 1.5% Improper engine oil 1-2%
Vehicle class Mean mpg (MY2014) Cars 24.3 SUVs, crossovers 20.8 Pickup trucks 17.3 Vans, minivans 16.8
Level Factor Effect (MY2014) Strategic Vehicle class 45% Vehicle model Vehicle configuration 933% all cars 400% cars excluding EVs 485% all SUVs 138% SUVs excluding EVs 109% all pickups 29% cars, 59% pickups Out-of-tune engine 4-40% Tires with 25% higher rolling resistance 3-5% Tires underinflated by 5 psi 1.5% Improper engine oil 1-2%
Vehicle class Mpg (MY2014) Min Max Cars 12 124* SUVs, crossovers 13 76** Pickup trucks 11 23 Vans, minivans 11 24 * Best fully electric car: 124 mpg Best hybrid car: 50 mpg Best car with internal-combustion engine: 50 mpg ** Best fully electric SUV/crossover: 76 mpg Best hybrid SUV/crossover: 31 mpg Best SUV/crossover with internal-combustion engine: 29 mpg
Level Factor Effect (MY2014) Strategic Vehicle class 45% Vehicle model Vehicle configuration 933% all cars 400% cars excluding EVs 485% all SUVs 138% SUVs excluding EVs 109% all pickups 29% cars, 59% pickups Out-of-tune engine 4-40% Tires with 25% higher rolling resistance 3-5% Tires underinflated by 5 psi 1.5% Improper engine oil 1-2%
Vehicle class Mean number of variants Mean mpg range Cars 5.3 7.1 SUVs, crossovers 3.8 6.7 Pickup trucks 3.4 10.2 Vans, minivans 5.3 8.2
Level Factor Effect (MY2014) Strategic Vehicle class 45% Vehicle model Vehicle configuration 933% all cars 400% cars excluding EVs 485% all SUVs 138% SUVs excluding EVs 109% all pickups 29% cars, 59% pickups Out-of-tune engine 4-40% Tires with 25% higher rolling resistance 3-5% Tires underinflated by 5 psi 1.5% Improper engine oil 1-2%
Level Factor Effect Route selection: road type variable Tactical Route selection: grade profile 15-20% Route selection: congestion 20-40% Carrying extra 100 pounds 2%
Weight gain of adults Now vs. 1960: +25 pounds Reduction in fuel economy of up to 0.5% Exercise as a good eco-driving practice
Level Factor Effect Idling variable Driving at very high speeds 30% Operational Not using cruise control 7% (while at highway speeds) Using air conditioner 5-25% Aggressive driving 20-30%
Two scenarios Most fuel-efficient gasoline car (50 mpg), but the driver disregards all other good eco-driving practices Least fuel-efficient car (12 mpg), but the driver follows all other good eco-driving practices
Factor Effect on performance Fuel economy (mpg) Nominal performance -- 50.0 Aggressive driving -25% 37.5 Driving at excessively high speeds -6% 35.3 Route selection -6% 33.1 (road type, grade, and congestion) Out-of-tune engine -4% 31.8 Tires with increased rolling resistance -4% 30.5 Using air conditioner -4% 29.3 Excessive idling -2% 38.7 Extra weight -1.5% 28.3 Improper oil -1.5% 27.9 Under-inflated tires -1.5% 27.5
Factor Effect on performance Fuel economy (mpg) Nominal performance -- 50.0 Aggressive driving -25% 37.5 Driving at excessively high speeds -6% 35.3 Route selection SAFETY-RELATED -6% 33.1 (road type, grade, and congestion) Out-of-tune engine 31% -4% 31.8 Tires with increased rolling resistance -4% 30.5 Using air conditioner -4% 29.3 Excessive idling -2% 38.7 Extra weight -1.5% 28.3 Improper oil -1.5% 27.9 Under-inflated tires -1.5% 27.5
Factor Effect on performance Fuel economy (mpg) Nominal performance -- 50.0 Aggressive driving -25% 37.5 Driving at excessively high speeds -6% 35.3 Route selection (road type, grade, and congestion) -6% 33.1 Out-of-tune engine -4% 31.8 SELF-DRIVING VEHICLES Tires with increased rolling resistance -4% 30.5 Using air conditioner 37% -4% 29.3 Excessive idling -2% 38.7 Extra weight -1.5% 28.3 Improper oil -1.5% 27.9 Under-inflated tires -1.5% 27.5
Conclusions Vehicle selection has, by far, the most dominant effect The remaining factors that a driver has control over can contribute, in total, to about a 45% reduction in fuel economy
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