5 ms·
Very good concept overall, I like the idea A LOT. One thing that surprised me: >> Speeding doesn't save as much time as you might think, but driving 10 MPH over
by isalmon 14y ago
Very good concept overall, I like the idea A LOT. One thing that surprised me:
>> Speeding doesn't save as much time as you might think, but driving 10 MPH over the speed limit reduces fuel efficiency by 12-15%.
How's my fuel efficiency related to the speed limit set by local authorities?
- garethadams 14y agoI think it's probably saying that every 10MPH increase has a corresponding fuel efficiency hit
- dbrian 14y agoObviously it varies by car but the the theory is that most engines are less fuel efficient at higher speeds. So driving the speed limit is more fuel efficient than driving over the speed limit.
- acgourley 14y agoThey mean common US freeway speeds of course, shortened for copy punch/length.
- smileysteve 14y agoThe highest gear's most efficient peak of most "consumer" cars maximizes efficiency around 65mph. The NHTSA considered efficiency along with safety when making their recommendation so many years ago.
- nawitus 14y ago65mph is slightly too high for most models. http://en.wikipedia.org/wiki/File:Fuel_economy_vs_speed_1997.png http://en.wikipedia.org/wiki/File:Fuel_economy_vs_speed_1997...
- thejo 14y agoHey isalmon, fuel efficiency is not related to the speed limit. We just use that as a frame of reference. The actual numbers are that fuel efficiency drops by 12-15% for every 10 mph above 50 mph. Here's an article which talks about that - http://www.greencarcongress.com/2013/01/thomas-20130117.html http://www.greencarcongress.com/2013/01/thomas-20130117.html
- isalmon 14y agoWell, I guess you should clarify it then on the website? Does not really help your credibility ;)
- mistercow 14y agoThat data includes cars going back to 1984. From what I have heard (and have no citation for this), newer cars remain efficient at higher speeds than 50 mph. Do you know if that's true?
- danielweber 14y agoThe biggest change is air resistance. Some day when you are on a freeway without many other cars around, shift into neutral. Depending on your car model, you will lose 1-2 mph every second until you get to around 50 mph, when you will lose speed much more slowly. On a flat road it might take you a whole minute to drop the next 10 mph. (Make sure you are in the right hand land before doing stuff like this. Also be aware that driving too slow can be as dangerous as driving too fast.)
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- sigkill 14y agoI wonder if some wing tech were possible to be used on vehicle body as an aftermarket option to increase laminar flow (or delay separation, I'm not sure, not an AE) to reduce air resistance.
- danielweber 14y agoI've seen hypermilers put aeroshells (don't know the proper name) on the backs of their cars to reduce air friction. It's pretty simple to do, but it looks very trashy.