High strength steel is used to protect the passenger compartment.

More manufacturers are using high strength steel.

As with most other technologies, high strength steel was first used in high-end luxury cars. It is stronger than conventional steel and costs more as well.

However, over the last few years it has tricked down into more mainstream vehicles as it has proven to make a vehicle stronger and resist intrusion into the passenger compartment better than conventional steel.

Cars are designed to crumple during an accident. In fact, vehicles have an area in the front and back which are known as crumple zones.

These areas fold like an accordion to absorb the force of an impact before it reaches the passenger compartment. High strength steel is used around the passenger compartment to ensure that a high speed impact doesn't overcome the crumple zones and intrude on the passenger compartment.

Boron steel is a high strength steel which is commonly used in the A, B, and C pillars of a vehicle (these are the pillars which essentially attach the roof to the rest of the car). A few sport utility vehicles on the market use Boron in the pillars and the roof.

High strength steel in SUV's.

As SUV's are more prone to rollovers, using it to reinforce the roof reduces the chance of the roof caving in if the vehicle rolls over many times. This is a break-through in SUV safety technology. The first SUV to offer Boron in the roof was the Volvo XC90.

Although more manufacturers are using better materials such as Boron, some have not. It is not yet mandatory and manufacturers which are concerned about offering a low price do not use it at all, or to the degree to which they should.

Most European manufacturers use Boron as European safety standards are stricter.

As you can see from these two images, the design and quality of materials is the most important factor in passive safety.

As shown in the vehicle above, a well designed car, truck, or SUV, should absorb the energy before it reached the passenger compartment.

As we see in the picture below, if the energy is not properly absorbed and distributed it will enter the passenger compartment and cause serious injury to the occpuants.

High strength steel in conjunction with other passive safety systems such as seatbelts and airbags, provide the ultimate protection in case of an accident.