Despite all the auto-tech brain-power in this world, fully electronic brakes—
which would replace brake fluid with lighter, quicker wires and motors—have yet to arrive. The long-standing obstacle: Industry-standard 12-volt electrical systems can’t drive a motor powerful enough to stop a two-ton sedan. The prototype Electronic Wedge Brake, by German company Siemens, solves this problem by tapping the vehicle’s own energy to slow itself down. Electric motors [1] drive screwjacks [2] that move a corrugated outer plate [3] fore and aft in plane with the rotor [4].

» Slideshow: How Roll Stability Control works

With 302 horses at your disposal, you'd think that stopping the 2002 Mercedes SL500 convertible would be an issue. Not so.


The car features the first brake-by-wire system. Hit the brakes and a computer begins slowing you within a fraction of a second. The system also determines which wheels have the most traction and applies the brakes accordingly to prevent a skid.


And just in case it pulls a Windows 98 on you, hydraulics act as a backup. Available next spring; price not set.