German motoring group ADAC has discovered some cabrio convertibles have minimal real-world rollover protection.
ADAC results released last week demonstrate the effectiveness of various rollover systems in three cars: the Peugeot 207 CC, Mini Cooper and Citroen C3 Pluriel.
All three were subjected to a 50km/h rollover off a specially designed sled with four crash-test dummies belted into each car.
The cars were chosen because all had different degrees of protection and were representative of the type of protection available in other cabrio-convertibles.
The Peugeot 207CC has an active rollover system and the Mini a passive one. ADAC describes the Pluriel as being “without significant rollover protection”.
Of the three, the 207 performed best, but rolled twice. The Pluriel and Mini each rolled four times.
ADAC found that all three cars had too much slack in their seatbelts to hold occupants properly in a rollover.
The Peugeot's standard seatbelt pre-tensioners did manage to hold front-seat occupants more securely.
ADAC says there is a risk of head injuries to people in the Mini Cooper because of the “unfavourable geometry” of the seatbelts, and the built-in passive roll bars behind the rear seats are good only for people shorter than 175cm. However, the car rated as “satisfactory” in the test.
The Pluriel rated “poor”, despite meeting German TUV standard rollover criteria and achieving a four-star EuroNCAP crash score.
With its roof completely open, the Pluriel fared worst. ADAC says the A-pillars collapsed, seatbelt positioning was poor and the roll bars were inadequate to protect all but the shortest of occupants.
In the Peugeot, the automatic rollbar behind the rear seats deployed and gave the rear passengers better protection. But the front A-pillar showed significant deformation under load and subsequently provided less protection for front passengers.
The Mini had the best results for A-pillar strength.
In an effort to improve occupant safety, ADAC has asked carmakers for stronger A-pillars, better seatbelt design and increased survival space through higher rollbars.
It also suggested electronic stability control could reduce the incidence of rollovers, thereby avoiding the problem altogether.
Electronic stability control has been mandated for all cars in Europe.
ADAC has 15 million members in Germany. It has previously tested the Mazda MX5, Opel Astra convertible and Volkswagen Beetle convertible.