What psychological reason did automakers introduce by engineering gauges to read well below the actual "E" mark before running dry?

Answer

To provide an illusion of extra leeway before the true emergency point

Deliberate buffer zones below 'E' are engineered to give drivers a feeling of extra time or leeway before they actually risk running out of gasoline, alongside making the tank seem fuller for longer after filling up.

 What psychological reason did automakers introduce by engineering gauges to read well below the actual "E" mark before running dry?
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