Mercedes-Benz developed a groundbreaking safety feature for its R129 convertible cars to prevent a serious risk that threatened the very existence of convertibles.
In the 1970s, growing concerns about rollover accidents put the future of convertible cars at risk. Regulators proposed new rules to improve rollover safety because drivers and passengers could suffer severe injuries — in some cases, literally losing their heads — if their cars flipped without proper protection.
Mercedes-Benz did not want convertibles to vanish from the roads. To keep them alive and safe, the company introduced an innovative solution in its 1989 R129 generation SL-Class.
During the 1950s and early 1960s, convertibles were very popular. But by the late 1960s and 1970s, their popularity dropped sharply. For instance, sales of the Ford Mustang convertible fell from 22.8% of the Mustang market in 1965 to just 3.9% by 1970.
The lack of rollover protection was a major reason behind this decline. Convertibles had no roof or structure to protect occupants if the car rolled over during an accident.
Mercedes-Benz engineers responded by creating a stronger A-pillar and designing an automatic rollover bar placed behind the seats. This bar was mounted on hydraulic springs and could deploy in less than a second if a rollover was detected.
When triggered, the roll bar would shoot up and hit the ground first, helping to push the car back onto its wheels. This innovative system significantly improved safety for convertible drivers and passengers.
The R129’s safety feature was so effective that it set a new standard. Today, similar rollover protection systems are common in convertibles worldwide.
The R129 itself has become a classic car, with the most affordable model, the 300 SL featuring a 3.0-liter inline-six engine, available for around $20,000.
Thanks to Mercedes-Benz’s ingenuity, convertibles not only survived regulatory pressure but also became safer than ever before. Without this invention, the convertible might have disappeared from the roads altogether.
