This invention relates to a device for mounting posts or poles in a foundation. As shown in Figure 1c one design consists of supports (2) attached both to the casing (3) and to the flange of the post (1). Figure 1a shows the extra bend or bends (4) with which the supports are provided, one or more of which are stretched when the casing of the post is demolished by a vehicle. The invention is of particular advantage when applied to yielding posts or poles of thin sheet metal which are normally cut off when hit by a vehicle, the supports stretching and restraining both the post and the vehicle.