L/100km vs MPG: Inverse Scales & The MPG Illusion
L/100km and MPG are inverse metrics. One measures fuel consumption (volume per distance), while the other measures fuel economy (distance per volume). This difference creates a well-documented cognitive bias known as the MPG Illusion.
The number 235.214583 is the universal constant linking US miles per gallon and liters per 100 kilometers.
The MPG Illusion Explained
Researchers Richard Larrick and Jack Soll at Duke University coined the term "The MPG Illusion" to explain how human intuition misjudges fuel savings.
Consider two vehicle upgrades: Person A replaces a 15 MPG truck with a 20 MPG crossover. Person B replaces a 35 MPG sedan with a 50 MPG hybrid. Who saves more fuel over 10,000 miles of driving?
Most people intuitively guess Person B because 50 - 35 = +15 MPG, while 20 - 15 = +5 MPG. Mathematically, this intuition is completely wrong.
Person A: 10,000 ÷ 15 = 666.7 gal. 10,000 ÷ 20 = 500.0 gal. Fuel saved: 166.7 gallons!
Person B: 10,000 ÷ 35 = 285.7 gal. 10,000 ÷ 50 = 200.0 gal. Fuel saved: 85.7 gallons.
Person A saved nearly TWICE as much gasoline as Person B! Because L/100km is linear with respect to fuel consumed, it prevents this cognitive illusion entirely.
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