Augutus' House and Livias' House

Wendy, I think you're confusing the Arch of Titus with the Arch of Constantine - which is near the Colosseum. The Arch of Titus is on the Via Sacra just beyond the entry gate to the Roman Forum so you need to go through the entrance/security check. It's very near a (beyond the gate) access point to the Palatine, and there's a ticket office there:

From coopculture:
"Ticket office of the Arch of Titus:
The access gate Arco di Tito will be open again from 11th of March. This is just an access, not an exit."

If you use the map on the coopculture site, you can see where it is. Use the satellite view:

http://www.coopculture.it/en/heritage.cfm?id=4

Click on "Find it on the map"

Find the street marked "Via Sacra" between Colosseum and Piazza Santa Maria Nova, and zoom in. You'll see "Arco di Tito" marked. Using satellite view, zoom in some more and you'll see where the gate/ticket office is, and that the arch is just beyond it.

Thanks Kathy for the detailed reply. I am still a bit confused after looking at the map. If I start from Colosseum, i just walk west on Via Sacra. But the entrance to Roman Forum is far away. If I go to the ticket booth at the Arch Titus, and I am using roma pass, does that mean I have used my one entrance to the Roman Forum?

Thanks

It doesn't matter if you enter through the palatine hill or forum entrance. Once you're inside one, you're inside both. There is an internal walkway connecting the two sites, making them a single site as far as the pass or entry tickets are concerned.

Donna

There is more than one entrance to the Forum: the other is off of Via dei Fori Imperiali on the North side. The one on Via Sacra is closest to the meeting point for the tour of the Palatine as the Arch of Titus will be right there. Again, the two sites are interconnected: they can be accessed without having to leave the secured area of one to get to the other. Your tour will head off to the south of the arch directly into the Palatine without going through separate ticketed gate/entry.

When your tour is over, you can also retrace steps back to the Forum for a look around as long as you do not leave the secured area/exit gates.

Thank you all. I think I understood it finally!