The only clue is that it was a location on the 1979 tour so it could be a road almost anywhere across 2 continents. You can exclude the UK due to the road markings. I can't believe some of you are so close.
Not that many choices? You're joking right? 
I'm obviously missing something. I tried and was able to drag the pin to anywhere in the world. How are there not many choices?
When I saw the picture I thought "this looks like a road in the US". Then, I googled some major highways in the US and I've found the scenery which reminds me the scenery of the cover. So then what I did was I did a little research and found a place which looks pretty close to cover.
So I've picked that out and the answer was "169KM". 169KM is not an infinity, in fact there's only maybe a dozen of capable roads in this area.
Now, this is where this competition gets pretty annoying. Because knowing you're 169KM off you can with a little bit of research find the exact place. It would be much, much better if the website would just tell you something like "you're close" or "you're too far" or something, not the exact number. With the system like that, you can guarantee to have thousands of close answers.
