In case you missed my last article detailing my passionate hatred for the latest bit of consumer stupidity, known as hybrid automobiles, I’m back with a sequel piece. Here I’ll be employing the mighty power known as *algebra* to explain why buying a hybrid automobile makes no economic sense, except in what would be best classified as a nightmare scenario. To illustrate this, I want to compare the Toyota Prius with (in my opinion at least) one of the best inexpensive cars on the market, the Toyota Corolla. The cars are of a similar size and equal seating capacity (5). So what makes the humble Corolla more than a match for the mighty Prius from an economic perspective? The answer is simple: cost.

Consider the following vital stats about the two automobiles:

Car | City MPG | Highway MPG | MSRP Range |

2008 Prius | 48 | 45 | $21,100 — $23,370 |

2008 Corolla | 28 | 37 | $14,405 — $16,415 |

According to Uncle Sam, it’s plausible to assume that the average driver puts about 15k miles on a car every year. Likewise, according to the DOT, the average American keeps their car about 4.5 years. That’s not a whole lot of time to recover the cost of the vastly more expensive Prius. But with the price of gas these days, it has to be a good deal, right? Wrong.

Assuming that the cars depreciate at an equal rate (or you just crash them into a tree and get nothing from your insurance company) and that inflation (now pushing 4% per year) drops to zero, here’s where the Prius becomes cheaper as determined by the price of gas (here we only consider the lowest end model of each car):

When the Prius | Price of Gasoline (per gallon) | ||||

Costs Less | $2.00 | $3.26 | $5.00 | $8.00 | $10.00 |

Years | 22.8 | 14.1 | 9.1 | 5.7 | 4.6 |

So for a Prius to be more economically sensible for the “average” American, gas has to cost $10.00 a gallon. And this is assuming 0% inflation. The numbers get worse when you factor in a 3% inflation rate. Assume that the gas price listed is the price today and that the cost of gas increases inline with the 3% inflation rate (Ben Bernanke and I are both being hopeful). Then the crossover point looks like:

When the Prius | Price of Gasoline (per gallon) | ||||

Costs Less | $2.00 | $3.26 | $5.00 | $8.00 | $10.00 |

Years | 36 | 18 | 11 | 6 | 5 |

So unless we assume that gas prices are going to head up significantly faster than the inflation rate, it’ll still take $10.00 per gallon gasoline to make the mightly Prius cost-competitive with the humble Corolla. Perhaps that’s something to think about the next time you head to visit the Toyota dealer…