6 ms·

You don't see a whole lot of distinct raindrop shapes for a very good reason: path of least resistance.

jessriedel 11y ago
The question isn't "why is there only one shape that minimizes drag?", the question is "why are all the cars sacrificing so much style and functionality to reduce drag?". You would expect some buyers to accept slightly less fuel economy for increased style, especially in luxury case, since they clearly are willing to pay significantly extra for style in ways that don't conflict with fuel economy (e.g., leather seats). The reason is that the market is not being determined by having the consumer trade off style/functionality for fuel economy. Rather, the fuel economy, and hence the shape, is being set by statute. That's why even luxury cars have about the same shape. The only exception are the super luxury cars that make up such a small fraction of the market that they are negligible in calculating a manufacturer's fleet-average fuel economy (which is what the regulation specifies).
- redblacktree 11y ago
  > slightly less fuel economy I think the issue is that it isn't slight. Air resistance increases in a cubic ratio to speed. Aerodynamics make a big difference at highway speeds.
  - jessriedel 11y ago
    They knew aerodynamics in the 1950's too, and the fuel prices were very similar in inflation adjusted terms. http://inflationdata.com/inflation/images/charts/Oil/Gasoline_inflation_chart.htm http://inflationdata.com/inflation/images/charts/Oil/Gasolin... (And we are richer then we were before, so modern folks are more willing to pay extra for fashion). The difference between then and now is definitely regulatory.
    - dragonwriter 11y ago
      > And we are richer then we were before Well, that depends who "we" is. "Car owners" as a whole may well be poorer than in the 1950s in inflation adjusted terms: median income has gone up some, but car ownership has moved down the economic scale, too. And there are different looks at the top end of the market, the part that caters to people who are willing to pay extra for fashion.

The question isn't "why is there only one shape that minimizes drag?", the question is "why are all the cars sacrificing so much style and functionality to reduce drag?". You would expect some buyers to accept slightly less fuel economy for increased style, especially in luxury case, since they clearly are willing to pay significantly extra for style in ways that don't conflict with fuel economy (e.g., leather seats). The reason is that the market is not being determined by having the consumer trade off style/functionality for fuel economy. Rather, the fuel economy, and hence the shape, is being set by statute. That's why even luxury cars have about the same shape. The only exception are the super luxury cars that make up such a small fraction of the market that they are negligible in calculating a manufacturer's fleet-average fuel economy (which is what the regulation specifies).

redblacktree 11y ago
> slightly less fuel economy I think the issue is that it isn't slight. Air resistance increases in a cubic ratio to speed. Aerodynamics make a big difference at highway speeds.
- jessriedel 11y ago
  They knew aerodynamics in the 1950's too, and the fuel prices were very similar in inflation adjusted terms. http://inflationdata.com/inflation/images/charts/Oil/Gasoline_inflation_chart.htm http://inflationdata.com/inflation/images/charts/Oil/Gasolin... (And we are richer then we were before, so modern folks are more willing to pay extra for fashion). The difference between then and now is definitely regulatory.
  - dragonwriter 11y ago
    > And we are richer then we were before Well, that depends who "we" is. "Car owners" as a whole may well be poorer than in the 1950s in inflation adjusted terms: median income has gone up some, but car ownership has moved down the economic scale, too. And there are different looks at the top end of the market, the part that caters to people who are willing to pay extra for fashion.