A similar scenario was covered in a recent episode of "Dual Survival" (or what I like to call "The Survival Odd Couple"). The two were stranded on a logging road in Maine, and had to decide what to do with limited supplies.

The episode highlighted two necessary pieces of information that are not presented here, but could be easily determined by direct observation. First, is the area where the vehicle is stuck clean and open? If not, the smoke from signal fires will likely be diffused by the tree cluster, and rescuers will have difficulty locating you by air. Second, is there any indication that the road has been recently travelled? Looking at the road beyond the fallen tree could reveal such signs.

For me, an enclosed area means I'm walking, regardless of the road. An open area and recent road activity means I'm definitely staying. An open area with little activity means I will try my best with a signal fire and recon the area for the first 24 hours. I imagine the quality of the nearby water will be the deciding factor, since I have no means of purifying it. Once the bottled water runs out, I'll want to start walking towards civilization (and antibiotics) so I can get rid of the critters I ingested from the little streams as soon as possible.