Small car, strong safety

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 car's occupants are protected by a steel housing that combines longitudinal and transverse members that transmit impact forces over a large area of the car. So it's not about the amount of steel between you and the truck that hits you - it's about how that impact is controlled and dissipated. That's what the TRIDION safety cell is all about. Watch: Godzilla (a separate window will open.) or watch the Crash Movie.

What’s a crash box?

The smart fortwo is designed with two crash boxes. The front box, sitting in front of the TRIDION safety cell is reinforced with transverse members and slip tubes that crumple in an accident.

For parking lot bumps, an impact of less than 2 miles an hour won't affect the crash box at all. Up to 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.

At the rear of the car the rear crash box is built of aluminum, which crumples much like the front slip tubes do. Fuel supply is stopped in the event of a crash 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 we bet you haven't thought of that as a safety feature. If you suffer a side impact in your smart car, 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 can help to absorb the impact. Of course, each door also has a side impact barrier installed. In European NCAP crash tests, the smart car's passenger cell remained rigid at impact speeds of 45 miles an hour allowing both doors to open easily.

Active Safety

The smart fortwo is packed with a long list of active safety features that will introduce you to a whole new set of acronyms and keep you safer in the process:

			Electronic Stability Program or ESP® When the ESP® sensors indicate a skid or swerving of your car, they automatically control the engine throttle and the Anti-Lock brakes to bring the car back under control.
			Anti-Lock Brake Systems (ABS)+ Most cars have ABS, but smart takes things one step further by adding Electronic Brake-Force Distribution Control (EBD). With ABS, you can hit your brakes hard knowing the ABS circuitry will apply and release each brake independently to keep you from skidding. EBD then optimizes the front-to-rear balance of braking to allow you to steer without loss of control.
			Cornering Brake Control (CBC) When you enter a corner and apply your brakes, the unequal forces at each wheel can result in a skid or a complete "end-around". With CBC your smart fortwo controls the braking force at each wheel to keep you headed where the car is steered.
			Electronic Brake Assist (EBA) Avoiding accidents is often measured in inches. EBA can sense when you have stepped on the brake quickly but have not applied it hard enough to activate the ABS system. It can be the difference in reaction time you need to avoid an accident.
			Acceleration Skid Control (ASC) ASC allows your smart fortwo to move forward on slippery surfaces. ASC acts much like a differential lock but does it by selectively braking the wheels that are losing traction. Plus, Engine Torque Control (ETC) provides engine control when driving on slippery surfaces. It "feathers" the throttle on low traction acceleration and limits torque in down shifting applications.
			Hill Start Assist (HSA) The auto/manual transmission of the smart fortwo is equipped with HSA which allows you to pull away on a hill without having to apply the handbrake. As you lift your foot from the brake pedal while sitting stopped on a hill, HSA holds the brakes on for .7 seconds to give you time to move your foot to the accelerator. So don't worry about driving your smart fortwo in San Francisco.

Passive Safety

	The frame for smart cars is made of reinforced steel, and protects like a Walnut shell as seen in this crash test of the smart fortwo vs. a much larger Mercedes. (Larger view)

All smart cars are equipped with a package of passive safety features. Full driver and passenger front airbags are standard. A collapsible steering column will retract in the event of a serious front-end collision, minimizing the likelihood of injury.

The smart fortwo also has intelligent seats. They incorporate seatbelt tensioners that sense motion changes to reduce slack in a few milliseconds while also triggering a belt force limiter that releases a controlled amount of pressure on the chest before it becomes too great. In addition, the seats are designed with a strong modular steel structure with integrated headrests.