When you are on the leading edge of vehicle efficiency and small vehicle design, the issue of safety is a critical element. That's why the core design philosophy of the smart fortwo is focused on something called the tridion safety cell. Much like a nut is protected by its hard outside shell, the smart fortwo's occupants are protected by a steel housing that combines longitudinal and transverse members that displace impact forces over a large area of the car. So it's not about the amount of steel, but how that material will resist an impact. That's what the tridion safety cell is all about.

What's a crash box?

The smart fortwo is designed with steel bumpers at the front and rear that are bolted to the safety cell´s longitudinal beams via slip tubes. They can be replaced after minor collisions at low costs. For parking lot bumps, an impact of less than 2 miles an hour won't affect the crash box at all. Up to about 10 miles per hour, the slip tubes move to keep impact away from the tridion safety cell. Over 10 miles an hour, the tridion safety cell transmits impact over its entire surface to dissipate energy and protect its occupants (assuming a perpendicular impact involving the entire front width). At the rear of the car, the crash box is also built of steel, which crumples much like the front slip tubes do. At an impact exceeding the severity threshold, the fuel supply to the engine is stopped and the central locking system is automatically unlocked.

Side impact strength

You might have noticed that the smart fortwo has a pretty short wheelbase, but you probably haven't thought of that as a safety feature. If you suffer a side impact in your smart fortwo, chances are that the car hitting you will hit the wheels and tires of your car. Those wheels and tires are connected to either longitudinal structural members or axles that help to displace the crash energy. Each door also has a side brace installed.