Mercedes quickly responded halting sales for a time and doing a "crash" development program to add electronic stability control. From a crash safety standpoint the A-Class had a unique design with a sandwich double floor that allowed the engine to slide under the floor in the event of a frontal collision. The A-Class platform was Mercedes first front wheel drive car and has been used as a test bed for battery and fuel cell development. The third generation model was due in 2011 but it now looks like it may be canceled.
[Source: Automotive News - Sub. req'd]