Why at 12'o clock all vehicles are stop on hawara bridge?

It is so because on the bridge there is one clock which do not work whit a cell , battery or solar panels and the scientist who has made this clock and said that "when this clock will stop working that time 12 o'clock will be in this clock and at that time that bridge will also broke so every one stop going on that bridge before 12 o'clock and at 12 o'clock