There's no other way in but this narrow bridge,actually only a walkway.
There is a car park at the beginning (around 50 places... i won't bet in a place in high season: you can also walk from the center of Bagnoregio (not long, but up and down) or park along the way, if you arrive by car.
In theory you have to pay for the parking (buy a ticket from the shop around and scrape away the surface to mark the beginning time) but when i was there in april, they told me the tickets finished and was not till then resupplyed by the municipality. If still so.... simply park!
You don't exactly reach the 'pedestrian bridge' when you are in Bagnoregio.
You would want to go to Civita de Bagnoregio which is about 20 minutes walking from Bagnoregio village to the base of the pedestrian bridge.
Of course if you have a car, once you arrive in Bagnoregio, you could just drive to the base of the bridge; Park your car & walk up the pedestrian bridge to the top of Civita de Bagnoregio...Simple as that !
Photo shows another bus ticket for me reaching in/out of Civita de Bagnoregio...
How to reach here ?
Well, depends on where you want to start ?
The best way is of course if you have a car, your own transport then it would be much much easier for you guys to reach this great place !
If like me, you want to be adventurous...then, follow these routes. Ready ?
First, if from Rome, take a bus or train to Viterbo; Viterbo is a nice town with many attractions too bad that VT doesn't list this place on its own.
Okay...from Viterbo, take a bus Bagnoregio ! Simple yes ?
The problem is buses are scarce & you might have to change a few buses along the way ! Be adventurous, like me !
Or, you could also reach Bagnoregio from Orvieto, change 2 buses the most...
The photo shows the COTRAL BUS 's ticket (one of the tickets...) that I purchased on the buses, on various destinations in/out Bagnoregio.
Good Luck !