I´m not from US...
i need this to put in a kart with a 12V bat... (so , nothing illegal here) just some guys having fun while karting
i also have instaled a siren, it looks great going after my mates
these lights would complete the scenery
Auto supply stores sell ready made ones--- you can get either xenon strobe or the ultra-brite LED type. In the US they are legal for use on certain vehicles. Highway construction vehicles use them as well as fire and other emergency personnel vehicles. They are not limited to just law enforcement. Even private snow plowers use them... more often they opt for the flashing amber strobes. I believe the website at Univ. of Guelph has a circuit that you can build submitted by Tony vanRoon. It alternately flashes your existing headlamps.
The hardware solution is two oscilators with about a 6:1 frequency ratio. The fast one flashes the lights and the slow one is used to select left or right. Run these to a decoder and the flash oscillator goes to either the left circuit or the right circuit.
I guess you could also use a single oscilllator, a divide by six counter and a decoder. Same idea really, but then the two signals would be syncronous.