My 2008 smart started shaking real bad coming to a stop after exiting freeway. It's like the clutch stays connected. I've been told this is characteristic of the smart by Smart of Chandler, this didn't happen for the first 19,000 miles so I don't believe Kimberly Pinto, their service writer. Any one experiencing a violent shutter/shake, whole vehicle seems to shake up and down a couple inches rapidly several times.
They have it now and wanted to give it back, but i called the service manager and we'll go for ride tomorrow..it happened the last two times i drove it....so hopefully it'll act up, but having been a shop supervisor for decades i know what can happen.....they can keep it 'til it acts up on them..
Not Normal no matter what they tell you.
Take them for a test drive if it is something you can reproduce. Your still under warranty and they should fix it.
My first thought was maybe something going wrong with the brake system.... maybe warped rotors.... but don't think that'd do anything close to "a couple inches". Could be the clutch not disengaging completely.... but i'm not really a mechanic, so i dunno.