The price displayed above that third button on the gas pump averaged more than $5.40 for several days this spring. American drivers still couldn’t get enough.

Premium gas now costs around a buck a gallon more than regular – way more than the price “premium” that drivers paid for the higher-octane stuff a decade ago.

Yet demand for premium gas is up. That makes some sense: More new vehicles recommend or require premium-grade octane levels of at least 91. But many drivers falsely believe high-octane gas offers a kind of treat for their engines.

High gas prices during the Iran war never really changed Americans’ driving habits. That’s particularly true for owners of higher-end SUVs, trucks and luxury cars that actually need a higher octane level.

Whatever the reason for the rise in demand, gas stations have turbocharged price hikes for premium gas over the past couple decades, creating a profit engine for station owners.