Rigid Safety Cell
Wondering why US streets are any different from streets in London, Paris, Tokyo, Kuala Lumpur ??
One of the safest cars in crash testing is the tiny Mercedes Smart Car, which has a rigid steel safety cell that far exceeds the abilities of larger cars like Volvo/BMW. It's not the size of the car, it's the design of the passenger cabin.
Most small cars in Europe have developed over the years to become 5* EuroNCAP in testing for safety - Honda Fit (known as the Honda Jazz in Europe) is a good example. The larger Ford Focus is another. You do not reduce your safety in a smaller car.
Gas Mileage > 50mpg.