Safety is about as easy for today's automotive engineers to tackle as the Hydra was for Hercules. For every head the Greek hero lopped off, not one but two grew in its place. Likewise, as soon as one safety issue is resolved, several others are likely to crop up in its place.

Take airbags, for example. Despite saving hundreds of lives, airbags unfortunately have proved dangerous to small adults, children and out-of-position occupants. While the development of so-called intelligent restraint systems goes on, the industry is attempting to deal with these problems through innovative methods.

Less publicized but no less critical than the airbag issue is the incidence of lower extremity injuries resulting from the intrusion of the footwell in severe accidents. According to NHTSA, even after full implementation of driver and passenger airbags, frontal impact crashes will still account for about 14,500 fatalities and 130,000 injuries per year, including 50,000 injuries to the lower limbs.

We reported on this subject in an article on floor systems in the August 1997 issue. Our sources indicated that the insurance industry and others would like to see FMVSS 208 expanded to include an offset barrier test. NHTSA is presently studying ECU Directive 96/79 EC as a possible supplemental regulation to U.S. Standard 208.

It appears the offset, partially overlapping barriers used in both the U.K. New Car Assessment Program (NCAP) and European Directive 96/79/EEC tests tend to produce much greater deformation of the passenger compartment than the traditional full-overlap testing. These findings were presented at IBEC '97 in Stuttgart, Germany, in October by Anthony Payne, a safety consultant for the Motor Industry Research Association, Warwickshire, England.

NHTSA, however, appears to be leaning toward a movable deformable barrier (MDB) test rather than the static offset crash test required in Europe. According to the agency, the MDB test more closely simulates vehicle-to-vehicle collisions, which account for 75 percent of frontal crashes.

Since it already has faced this problem, Mercedes developed an imaginative body engineering solution for the new A-Class. This ground-breaking vehicle features a canted footwell design, oblique engine installation and sandwich chassis and floor system construction, all of which work in concert to offer the same level of safety as the larger E-Class.

The A-Class also is significant in that it anticipates another looming safety issue ? compatibility, or the problem of collisions between different size vehicles. In the States, an increasing number of heavy sport-utility vehicles and minivans are sharing the highways with lighter passenger cars. This is another reason why NHTSA is looking so closely at the MDB test. According to the agency, fleet compatibility could improve as a result of the engineering required for different size vehicles to pass an MDB test.

Meanwhile, according to Ingo Kallina, vice president, passenger car components structure and safety, Mercedes already has dealt with this issue in the design of the A class. The result is a new benchmark that should lead the way toward further innovative concepts in both "passive" (body engineering) and "active" (restraints) safety at a time when new problems are arising and begging for solutions.