Abstract: A folding traffic-warning device includes an enclosure and enclosure base define first and second ballast compartments, which may be filed with sand, liquid or other material to provide stability during use. A circuit and a battery holder are carried between the first and second ballast compartments. The circuit provides power to a plurality of LEDs carried by a stationary light bar and first and second folding light bars. The folding light bars may be moved between an operational position and a storage position. An axle passing through the enclosure has an upper end attached to the stationary light bar and a lower end attached to a stabilizer bar. In an in-use or operational position, the stabilize bar is oriented perpendicular to the enclosure. In a storage position, the stabilizer bar is oriented parallel to the enclosure.