A C182 pilot completed a safe off-airport landing due to fuel exhaustion after the winds aloft increased above forecast which caused fuel usage to include his one hour fuel reserve.

Narrative

I ran out of gas; short of my destination. I took off with plenty of fuel (1 hour extra). I was going direct to my home base; usually a 2.5 hour trip. When I got to the halfway point I noticed my ground speed was about 120 MPH; not good for a C-182. I called Flight Watch and got the winds aloft for 9;000 FT; said 25 KTS. I changed my destination to buy some fuel and then head to my original destination. In the next hour the upper winds went to 40 KTS. When the engine started to sputter I had to look for a road to land on in the desert. I called Flight Watch again told them the head wind had almost doubled and gave him my latitude and longitude. I landed going south in the National Park on a narrow paved road. Landing roll was great. As I taxied looking for a place to get off the road ASAP; my left wing hit a cactus doing minor damage. I should have gotten an upper wind forecast before heading over to the coast. I could have picked up fuel at an airport on the river; all my fault. I talked to my Flight Service guy that night. He said indeed the winds had picked while I was enroute.