WHILE DRIVING ON AN EXPRESS WAY IN DALLAS, TEXAS MY GPS MADE AN ERROR CONCERNING AN EXIT AND I WAS REQUIRED TO DIVERT QUICKLY TO THE LEFT TO MAKE EXIT LANE .TIME WAS 6:00 PM ,HEAVY TRAFFIC CONDITIONS AND ROAD AND WEATHER CONDITIONS WERE EXCELLENT AND DRY. MY MERCEDES PRE ACTIVATED A SKID MODE AND THERE WAS APPROXIMATELY A 70% CUT BACK IN ENGINE POWER .A YELLOW ENGINE LIGHT CAME ON AND SKID MODE CAME ON OPERATOR SCREEN BUT THERE WAS NO SKIDDING TAKING PLACE. I WAS HELPLESS WITH NO POWER TO KEEP UP WITH THE 50-60 MPH TRAFFIC WHILE TRYING TO GET INTO LANE .CONSEQUENTLY A SEMI TRACTOR STRUCK MY LEFT REAR FENDER /BUMPER CAUSING DAMAGE TO MY MERCEDES. THERE WAS NO DAMAGE TO THE TRACTOR. ACCORDING TO MERCEDES THE VEHICLE WAS SUPPOSED TO DO THIS AS A SAFETY FEATURE. IF THIS IS TRUE THEN THEY ACTUALLY IN MY OPINION WHILE DEVELOPING SAFETY FEATURES CREATED ANOTHER UN SAFE CONDITION WHERE AS THE SEMI COULD HAVE RUN OVER MY WIFE AND I KILLING US BOTH. THIS WAS TRULY A NEAR MISS AND WE ARE VERY MUCH CONCERNED ABOUT IT HAPPENING AGAIN TO US OR SOME ONE ELSE, RESULTING IN A FATAL ACCIDENT, NOT JUST A FENDER BENDER. MERCEDES IS IN DENIAL CONCERNING ANY UN SAFE CONDITION AND REFUSED TO TAKE ANY RESPONSIBILITY FOR ANY DAMAGE THAT THIS CAR CAUSED. PLEASE REVIEW THIS VEHICLE FOR POSSIBLE CALL BACK BEFORE SOME ONE DOES GET SERIOUSLY INJURED. PERHAPS SKID MODE OR TRACTION CONTROL MAY BE HELPFUL BUT ENGINE CUT BACK AND POWER LOSS NEEDS TO BE LEFT TO THE OPERATOR NOT THE VEHICLE CONTROLLING IT'