In 1944, laminated glass was introduced in the PV model. After Vattenfall engineers presented their pioneering work to Volvo in the 1950s, Volvo engineer Nils Bohlin invented and patented the modern three-point safety belt, which became standard on all Volvo cars in 1959, and then made this design patent open in the interest of safety and made it available to other car manufacturers for free. Additionally, Volvo developed the first rear-facing child seat in 1964 and introduced its own booster seat in 1978.