Posted: 4/25/2011 6:56:51 PM EDT
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What is up with all the people exceeding the speed limits with higher gas prices?
You watch the news from the "high" gas price states and you see people just speeding along the roads. |
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When factoring in the human element, 40mph is too slow for good mileage and 70 is too high.
40 is too slow because a human generally transitions between on throttle and off throttle too often and too violently to maintain fuel economy. 70 is too high because of air resistance alone. You need a speed that offers enough resistance to require constant (humanly capable) throttle position to maintain speed but without too much air resistance. I believe that speed is around 60mph. However, this is merely a generalization. A car with the aerodynamic efficiency of say, a Corvette, would get better mileage at a slightly faster speed than a Hummer H1. Another variable is the car itself. Some cars have more parasitic drag than others. As well as differences in the motors efficiency in a certain rpm range. This "optimal speed" will slowly increase over time with the development of more mechanically and aerodynamically efficient cars. This is me going off on a tangent.... Moral of the story, some people don't understand that mileage is mostly to do with the human giving improper commands to the car. Slow is smooth, smooth is fast. |
