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reprinted from Automotive Engineering, June 2000

Motorcycle incorporates airbag system

Honda's fleet of Advanced Safety Vehicles includes a Gold Wing touring motorcycle equipped with an SRS airbag system

Honda's Advanced Safety Vehicle (ASV) project has moved into its second phase, with four vehicles representing the company's latest experimental safety technologies. Two of the ASV-2 vehicles are two-wheelers, designated vehicle Nos. 3 and 4. The ASV-2 No. 4 is a Gold Wing GL1500 Interstate touring motorcycle equipped with the airbag system Honda has been developing for some years. The GL1500 is a large motorcycle with a mass of 376 kg (830 lb) and a low center of gravity. It is equipped with a large windshield and has its fuel tank housed within the lower body structure. It is particularly suitable for installing an effective airbag system, according to Honda.

Honda says it considers that a positive aspect for airbags for motorcycles would be to reduce rider-ejection speeds through airbag deployment and to lessen injuries to the riders caused by contacts against other vehicles or road surfaces in accidents. Honda's analysis and experiments employed in the airbag research and development takes the premises that the rider is not primarily restrained, unlike the automotive application in which the airbag is the secondary restraint.

The prototype airbag measures 630 mm (25 in) high, 500 mm (20 in) wide, and 615 mm (24 in) in depth when deployed and has a volume of 120 L (4 ft3). The airbag must be securely reinforced and mounted to the motorcycle to be effective. It is elaborately fastened by three tethers connecting the rear and bottom sides and one tether connecting the left and right sides, and mounted at two points, one to the airbag module receptacle and the other to the motorcycle frame under the seat via two connecting straps.

The airbag's contact surface is V-shaped so that it could intercept a slightly out-of-position rider. Gas venting is critical after airbag deployment. If no vent hole is provided or the vents holes are too small, the rider might bounce back or even upward. Conversely, if venting should take place too rapidly through large holes, the airbag's effectiveness would be reduced. The prototype airbag has two vent holes, each with a 50-mm (2-in) diameter.

The Honda researchers caution that the motorcycle airbag system had both potential benefits as well as some adverse effects, and further research and development is needed. Accompanying the ASV-2 No. 4 motorcycle is an advanced helmet that has an energy absorbing capacity in rotational direction in addition to the to directional impact absorbing ability.

Jack Yamaguchi