AFAIK LEDs are not fired but typically supplied with a constant DC voltage. Yes, if that DC voltage is particularly dirty and rippled then you can see some LEDs flicker.
But that car exhibited a particular sequence while it doesn't appear that the other cars had. It also looks like the tail lights were pulsing as well. I suspect this was a deliberate mod. I can't see how rippled DC voltage supplied to LED lamp assemblies would generate such a specific pattern that meets up exactly right in the corner.