At the beginning of the 1970s, Mercedes-Benz built more than 30 test vehicles for research into future automotive safety systems as part of its in-house ESV (Experimental Safety Vehicle or in German: Experimental-Sicherheits-Fahrzeuge) program. They paved the way for a multitude of innovations, some of which could only be mass-produced years later. ESF 13, based on the W 114 series ("Stroke-Eight"), was the stylistically revised version of the ESF 5 and was presented at the 3rd International ESV Conference from May 30th to June 2nd, 1972 in Washington (USA).