Test note: influence of seat belts during frontal impacts at 50 km/h

In this document

This technical note, titled “Influence of seat belts”, presents the results of frontal impact tests at 50 km/h against a wall, carried out with crash test dummies equipped with acceleration and force sensors p. 23. The document specifies that these are recorded acceleration peaks, lasting only a few milliseconds p. 23.

Forces on the head

Without a seat belt, the impact on the windscreen generates a force of 2 tonnes; with a seat belt, it falls to 300 kg p. 23.

Forces on the thorax

Without a seat belt, the force can reach 6 tonnes; with a seat belt, it varies from 700 to 1,500 kg, depending on the vehicle whose decelerations vary from 30 to 60 g, i.e., 300 to 600 m/s² p. 23.

Forces on the femurs

Without a seat belt, the force can reach 1,500 kg; with a seat belt, it varies from 200 to 600 kg per leg p. 23.

Summary table of measurements (p. 23)

The document also provides the forces on the seat belt anchorages: on the floor, 1,500 kg on the central strap and 900 kg on the outer strap; on the B-pillar, 1,000 kg p. 23. Finally, the performance of the straps is indicated as “up to 3 tonnes” p. 23. A handwritten annotation “4” appears in the top right corner of the page p. 23.

Context

In the 1960s-1970s, the issue of automotive passive safety — including the seat belt — was the subject of numerous studies by manufacturers, at a time when its use was not yet generalised by French regulations (mandatory in the front from 1973). Citroën, like other manufacturers, conducted crash test campaigns to evaluate the effectiveness of this device against head, thoracic and lower limb injuries — these elements are part of general historical knowledge and are not mentioned in the document.

Archivist's perspective

This undated note is likely part of Paul Magès' broader work on passive safety and kinetic energy phenomena during impacts, a concern found in other items in the collection such as the demonstration on kinetic energy or the pedagogical dialogue on passive safety.

The rigour of the figures presented — orders of magnitude in tonnes and kilograms, decelerations in g — reflects an engineer's approach seeking to quantify objectively, almost brutally, the vital importance of wearing a seat belt. The striking contrast between the “without” and “with” seat belt values p. 23 suggests that this document could have served as a technical, or even pedagogical, argument in internal discussions or the dissemination of safety culture at Citroën.