If you ignore the ticket, your father is likely to have a
bench warrant sworn out against him.  That means they won't
hunt him down, but if an officer has contact with him for any
purpose, then the warrant may come up and he'll be taken
into custody until the issue is resolved.  A lot of "scofflaws"
don't realize the hassle that they may be in for at some
unexpected future time.

> The sign is marked School Zone..  uhm, school zones are 35 from
> 7:30-4:30

At least where the 15 MPH limit is posted, it applies any time that
children are present.  I don't know how the area was posted, but
my guess is that they can find you in violation if there were
kids milling around.

> The ticket was not certified mail, it was normal delivery
> in his po box.

I don't know what Tempe does, but Scottsdale delivers to the door
when the cited person does not respond, and I think they charge
for the personal service!  The photo radar should have a
recognizable picture of you behind the wheel.  A speeding charge
must be made against the driver personally, not just the owner
of the car.  But I think they're developing more ways of forcing
the owner to identify who was driving -- I guess you could make
a case for obstruction otherwise.

I'm not an anti-radar partisan, so I don't know all the legal
dodges that might be available.  If it's important for you to
keep clean, you might look up "photo radar" "driver" "prove"
or some such combination of things on google.com ...

Or call one of the law-yuhs who specialize in traffic offenses,
they will probably give you a little free advice by way of
screening your need for their service.  Finally, I think there
are public advocacy groups that give some advice, especially
groups that specialize in contesting speeding charges, and
they might balance the lawyers' bias.

Good luck anyway.

Vic