Lower retaining bolt between strut and wheel hub has failed causing head of bolt to shear off (see photos) on front passenger side suspension assembly. bolt head was found lying in driveway and sheared bolt was found on inspection of vehicle. vehicle may have been in motion at low speed or stationary at time of failure. appears to be material failure of the bolt in which a cracked formed and propagated across the bolt until the it could no longer withstand shear forces. am concerned about the 3 other retaining bolts on this vehicle at the other wheels.