I need some help collecting information about flashes and preflashes on speed and red light camera systems. If you live in an area with one, I would hugely appreciate it if you could help collect info and report it here. Sometimes the preflash is so fast that it's hard to notice, so be careful about that.

For example,

Brand: Gatso
Pictures Taken: Two
Flashes: one preflash and one flash per image, so four total flashes

I'm specifically interested in knowing whether or not they use a single flash to take a picture or a metering preflash before each image is taken.

Thanks in advance.