Keep in mind that indicators are of no use at all if people can't tell which direction they're flashing. At the very least they must be flashing on one side and steady on the other.

I think they need to also have a wide bar with at least 2 feet of separation between the lights or there's no way an approaching driver will be able to differentiate one side from the other until they get quite close.

No indicator is going to be as highly visible as a hand signal unless it's ridiculously large. Try Glo Gloves.