When returning my Hertz rental car to Termini station, I followed the GPS, but still made a crucial mistake at the final step. This article tries to explain the trickiest part of the route.
The rental car return address is "via Giolitti 267, Rome". The location is a multistory parking garage, and all rental car companies are at level 6-7. Set the address in your GPS, it should lead you to the intended location. However, when you approach the underpass, there are two separated roads, BOTH are going INTO the underpass, and you must use the road on the LEFT. See diagram below.
When I approached the underpass and saw the two divided roads, I thought the left one was for traffic exiting the underpass, so I chose the one on the right. When I emerged from the other side of the underpass and prepared to make a left turn, to my surprise , I was facing cars parked to my direction. Going forward would lead me into a ZTL zone. So I had to back out, drove around and approach the underpass from the other direction on Via Marsala.
.
ABOVE: You must turn into the LEFT entrance into the underpass.