There are 2 options to leaving Hana. One is to go back from where you came, back to Paia.  The other, is to keep going the same direction, which leads you back around.  Rental car agreements state you are not allowed to drive the second half of the Road to Hana unless you have a 4 x 4, but those rules are really outdated.  They used to apply years ago when the road was nothing but a rough dirt road.  Now, 85% of the road is a paved straight shot, except for 10 miles of unpaved road that should not be a problem for any car if the weather permits, and the ground is dry.  You may want to use more caution, or avoid the road, if it has rained. There are a few spots where driving up hill could be a little troublesome in wet conditions. The key is, if the posting on the board at the Ranger Station at `Ohe`o Gulch tells you that the road is open to all vehicles, then it is fine to drive. You will be back in Lahaina, Kihei or Wailea well short of what it would take you to retrace your steps back along the Hana Highway. Furthermore, while a bit rough, the road has far fewer turns, bridges and curves than the road to Hana from Paia, and is a much easier drive. Here is an example of a rough stretch of road. 

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