Read somewhere ages ago that car manufacturers won't fit linear gauges coz they create unrest -- ppl just don't like seeing that needle creep. So they actually forced some poor engineer to deliberately create gauges that act like a indicator light. You might as well have a light on the dash that glows red when there's trouble. (Come to think that's exactly what my old HQ holden did have
)
Don't know if it's true or not....