Turned Tyres
Drivers can be ticketed in San Francisco for not turning their wheels when they park. At first glimpse, it seems nonsensical - damaging tread by turning wheels when not moving means less grip when you really need it - but then you realise that the tyres are turned so that the car will roll into the kerb should the brakes fail. On streets as steep as San Francisco's, a runaway car could do some serious damage.