Normally, we like to end the week on an upbeat note, but this Friday, we’re fixated on slightly somber stuff — in particular, the BP oil spill/leak in the Gulf of Mexico. It’s just beginning to wash ashore in Louisiana, and it could soak beaches from Texas to Florida before all’s said and done. As a site that revels in rides of all sorts — from hybrid fuel-sippers to gas-guzzling supercars — we know that there’s a dark side to every car. Combustion engines rely on a vibrant petroleum industry, and that industry is the cause of the hurricane-shaped blob drifting toward the Louisiana coastline one month before storm season begins. Battery-electric vehicles are flawed, too: they need power plants, and the majority of those facilities in the U.S. are stoked by coal. [...]