A new type of passenger protection system, which could be installed for under $100, could be ready for 1973 or 1974 models, and features an automatically activated "security blanket" that restrains car passengers, was demonstrated recently by the Firestone Tire & Rubber Company in Detroit.

In development for two years by the Hamill Manufacturing Company, Washington, Mich., a Firestone subsidiary, the system recently has been given more emphasis because of the government's call for a restraint system by 1973 and signs of dissatisfaction for the air bag by some parts of the industry who say they cannot meet the January 1, 1973, deadline for bag installation.

Stored in a compartment at the lower edge of the back seat, and in the instrument panel for the front seat, the blanket of energy absorbing fabric is activated automatically at collision impact and prevents passengers from being hurled forward or sideways. It is deployed in 1/20th of a second and is designed to restrain three 200-pound persons in a head-on crash at 40 MPH. This exceeds the DOT standard requirement proposal of 30 MPH.

Because the blanket covers below the knees but not above the shoulders, vision is not obstructed but passengers are prevented from being thrown sideways into the door or from sliding down and under the restraint system.