According to Smart, this structure has longitudinal and transverse beams that displace impact forces over a large area of the car to protect occupants in a crash.   The tridion safety cell is available in black or silver, as elements of it, including the front pillars, are visible from the outside.   Smart says that slip tubes up front and a steel rear structure will prevent front and rear crashes of up to 10 mph from affecting the tridion cell.   Smart also says the wheels and tires, as well as side braces, will help dissipate energy in a side crash.  

The Smart design features wheels pushed outward to the corners of the car.   Up front, the Fortwo seems to be grinning, with its high-set headlights, central grille and open lower fascia that is also home to the optional fog lights.   The short hood leads to a tall windshield.   Along the sides, the exterior portions of the tridion safety cell trace the shape of each door.   The car ends shortly behind the seats, leaving a small hatchback opening at the back and giving both the coupe and convertible an egglike shape.  

At only 106.1 inches overall, 61.4 inches wide, 60.7 inches tall and 1808 pounds, the Fortwo is the smallest car offered in the United States.   By comparison, a Mini Cooper is nearly 40 inches longer and more than 750 pounds heavier.   While the length and width are quite small, the Fortwo is slightly taller than a Honda Fit, which gives it plenty of interior headroom.  

The convertible's top is power operated and has a heated glass rear window.   It has no latches to work and can be operated at any speed.   With the top down, a pair of structural beams can be removed from the roof above each door, creating an even freer open air feeling.   The up-level Passion coupe is available with a fixed glass roof with a manual sunshade.