Are we saving fuel, or just saving OUR fuel?

You should try increasing this. Reports are that higher pressure increases both tire life and mileage. Toyota recommendations are with a goal of cushiest ride. I run at 42/40 and current tank is at 57.5 mpg.

 

Yeah other people have recommended increasing the psi higher as well. I leave it at 35/33 mostly for the "cushier" ride. I may in future try to up the psi to around 40/38 or 42/40 for a full tank.

 

The reduction in rolling resistance from higher tire pressure really helps in urban driving situations where speeds are low. Because there is very little aerodynamic drag at low speeds, rolling resistance becomes very important. This especially true durning the warmup phase because your tires are cold and thus rolling resistance is at its highest. Reduce weight and reduce rolling resistance is the key to good fuel economy in the city. It helps on the highway too of course.

 

We have those here. In the link is a video explaining why they feel it works etc but as a motorist, I notice no difference and the adjusted speed limits aren't enforceable by law.

MoDOT's Gateway Guide - Variable Advisory Speeds

 

Notice that according to your link, due to minimal enforcement, they are no longer 'variable speed limits', just 'variable advisory speeds'.

 

That's pretty interesting. Looks like they've only had it up for a couple years, and adjusting human behavior would take longer than that. I'm always surprised at the number of cars that don't use FasTrak passes on Bay Area bridges, years now after introduction. They are stuck in long lines every day and yet they refuse to adapt. "You can lead a horse to water..."

 

I'd recommend upping the tire pressure to help MPG's AND to increase the life of your tires by improving the overall "wearing" of the tire. I got over 50,000 miles on my Yokohama's and the wear was even across the tire (at 44 PSI fronts and 42 PSI rears for the life of the tires). I would have tried for another 5,000 miles on these tires, but it was looking like the replacement tires I wanted to get would no longer be available in my size, so I opted for a new set of shoes.

 

So the only drawback is it would be easier to puncture your tire if you hit something like a pothole or whatever when driving then using lower pressure like what is recommended?

 

I read somewhere that higher pressures are LESS likely to result in a puncture than low pressures are. The reasoning was that the tire was less likely to deform against the rim and be cut by the edge of the rim. I would expect that higher pressures would put more strain on the suspension if you hit a pothole. But avoiding potholes and slowing down in a pothole-y area are good ideas in any case.

 

... or less likely to bend the rim itself.