What makes the 2009 Audi A4 sport sedan a leading choice among car buyers is its superb safety features that has been strongly confirmed by the US government’s passenger car safety tests. The A4 attained the highest rating of from the National Highway Traffic Safety Administration. Safety regulations in the US require passenger cars to pass the standard 30 mph (48 km/h) front and 33.5 mph (54 km/h) side crash tests.However, the New Car Assessment Program or NCAP, on which the A4’s performance was based, subjected the vehicle to tests that were 5 mph (8 km/h) faster than the regular crash tests, thus providing buyers more safety information. The ratings given by the NHTSA ranges from one star for the bottom performers to five stars for the highest.