base 12 is prevented to attach sign 10 to the roof of a vehicle a rubber suction cup 30 is attached at each corner of base 12 in addition slots 33 are provided in the front corner of sign 10 and slots 31 are provided at the two rear corners as best seen in the bottom view of fig3 as is to be understood sign 10 is to be oriented on the vehicle as indicated in fig3 with the front corner of the triangular base 12 aligned with the longitudinal axis of the vehicle and with rear panel 17 at right angles with the longitudinal axis of the vehicle thus a streamline structure is presented to the forward motion of the vehicle minimizing wind resistance and drag turning now to fig2 a cross sectional view of the sign 10 of fig1 is shown in the plane 2 2 thereof as will be noted a projection 20 is molded into top surface 18 to accept a light assembly 39 light assembly 39 includes a cable 35 which terminates in a plug 36 seen in fig1 which can be inserted in the cigarette lighter outlet of the vehicle to supply current to light assembly 39 details of a preferred light assembly 39 are shown in fig5 which provides a partial view of top surface 18 a lamp socket holder 42 may be formed from plastic tubing such as pvc pipe having an internal diameter to accept.