A restraint assembly of a type including a seat belt assembly and a side impact air bag assembly. The seat belt assembly and side impact assembly are preferably mounted to a motor vehicle seat. The seat belt assembly includes one or two retractors, preferably each having roto pretensioners. A single gas source is used to actuate retractor pretensioning functions, as well as providing a gas source for initiating the production of inflation gas for the side impact air bag assembly. Preferably, these elements are all mounted to a motor vehicle seat.