Electronic Stability Program (ESP®)
The standard-fitted ESP® system selectively controls the braking forces acting on the front and rear wheels in such a way as to reduce the risk of skids and slides and help the driver maintain control in critical situations. The system extends the technology of the anti-lock braking and acceleration skid control systems with a range of additional sensors which are used principally to detect skidding tendencies. The ESP® computer continuously compares the actual behaviour of the vehicle with the pre-programmed ideal values. The moment the car deviates from its ideal line, specially developed control logic causes the system to intervene with split-second speed, bringing the car back on track. It does this in two ways: by precisely controlled braking at one or more wheels and/or by reducing engine power. ESP® in this way both corrects driver errors and stabilises the vehicle in the event of skids due to wet, icy, gravelly or other adverse road surfaces where normally drivers would have little chance of maintaining control by steering or braking manoeuvres.

Sandwich concept
Compact cars like the Mercedes-Benz A-Class by definition have a shorter front section and thus present only limited deformation possibilities in an accident. Development work on the A-Class therefore focused on ways of making full use of the short crumple zone in the event of a frontal collision and clearing any components likely to adversely affect the deformation process out of the way. The components in question are primarily the engine and transmission, which undergo virtually no deformation and in a conventional-design compact car form a rigid block which can intrude into the passenger compartment, causing injury. The sandwich concept reduces this risk: in the A-Class the engine and transmission are positioned at an angle partly in front of and partly underneath the passenger compartment and in the event of a severe frontal collision can slide downwards out of the way. Thus the A-Class front end offers maximum possible deformation length. Without this "disappearing act" by the engine, the front section of the A-Class would have to be approximately 25 centimetres longer in order to offer occupants the same high level of protection. In a side impact too, the sandwich concept brings significant safety benefits due to the higher seating position of the occupants.

Sidebag
The standard sidebags in the A-Class are located in the front doors above the armrests. Sidebags for the rear are available as an option. In the event of a side impact, the sidebag tears open a seam in the door panel trim and inflates between the occupant and the door, thus preventing direct contact between the occupant and the door. This has a dual effect: as well as significantly reducing the forces exerted on the chest of the occupant sitting on the impact side, the sidebag also limits whiplash movement of the upper body.

TIREFIT
In Germany the A-Class comes as standard with the tyre sealant compound TIREFIT. Optionally, a conventional spare wheel is available at no extra cost. There are good reasons for omitting a spare wheel. For instance, statistics have shown that on average, motorists in central Europe are only unlucky enough to get a flat tyre once every 150,000 kilometres. Thus they can go for ten to twelve years without ever needing the spare wheel. The TIREFIT set takes up very little space in the boot and, including the electric pump, only adds about 2.2 kilograms to the weight. Furthermore, TIREFIT frees up the spare wheel recess to be used as additional stowage space. The tyre sealant compound is based on a special latex solution, which is particularly straightforward and clean to use, without the need for any tools or a jack. The sealant is pumped through the tyre valve, the tyre is inflated using the electric air pump and the car can then be driven at a speed of up to 80 km/h. The sealed tyre must be replaced with a new tyre at the next Mercedes workshop.