Southern Alaska has had: (M1.5 or greater) 1  9 earthquakes in the past 24 hours. 2  54 earthquakes in the past 7 days. 3  294 earthquakes in the past 30 days. 4  5,169 earthquakes in the past 365 days.
An engines idle speed is a programmed function. We cannot directly adjust the engine idle speed on a modern vehicle. The power control module or PCM provides all adjustments to the idle speed. Though no external engine idle speed adjustments are possible, many things can and do cause problems.
So the 85th percentile rule is simply a recognition that speed limits are set for the purposes of enforcement. And since law enforcement only has the resources to cite the most egregious violations, the speed limit is established at or near the 85th percentile, making only about 15% of free-flowing motorists violators.