in that compartment the remaining strobe lights in the other compartments will still operate and serve to warn oncoming traffic spaced along the top edge 58 of the container 44 are a plurality of bolts the bolt heads 60 being shown in fig3 and 4 as shown in fig4 the strobe lights 56 d include a light housing 62 mounted on a base 64 by pivot pins 66 a 66 b the pivot pins allow the light housing 62 to be pivoted to an optimal position for projecting light through the cover of the container as will be explained with reference to fig5 and 6 in fig5 a container 44 is shown buried in the roadway 32 at grade the sidewalls 46 a 46 b are shown along with the bottom 68 also being shown buried in the earth 70 at the top side 72 of the container which is open a first cover plate 74 is secured by bolts 76 having exposed heads 60 cover plate 74 is approximately 1 to 1 u00bd inches thick and has a rubber sealing gasket 78 compressed by the bolts 76 to seal the interior of the container 44 located above the cover plate 74 is a second cover plate 80 of approximately 2 to 3 inches in thickness and having a continuously curved exterior surface 82 the curvature of the cover plate 80 where allowed by.