Summary: We rounded up a selection of the most popular compact sedans to see which would rise to the top: the Toyota Corolla, Honda Civic, Mazda MAZDA3, Hyundai Elantra, Ford Focus, Chevy Cobalt or Nissan Sentra. Each of the cars in our comparison test featured an automatic transmission and four-cylinder engine and EPA-estimated highway fuel economy of at least 30 mpg. In the end, Kelley Blue Book subjected seven cars to more than 1,500 miles worth of poking, prodding and instrumented testing.