[Potato]

Another thing to consider is that many big rigs I've encountered often travel in excess of 100km/h and by following at the same speed, you aren't getting your optimal gas mileage. Depending on the speed and how close you tail the rig, it may actually cost you more gas to keep up.

Personally, I think 100ft is reasonably safe for me to follow a big rig. The driver can likely see me at that distance, and probably wouldn't be very annoyed since you aren't exactly tailgating. If that gets me 11% better mileage, then it's probably worth trying.

I've found following big rigs usually helps because you can often find one going 100-105 km/h and use it to help keep a pace (and with a truck in front of you, the speed demons seem to understand that you're only going the limit). Many of the trucks are themselves speed demons, but not all : )

I've found you can still get about 2-3% of benefit even a safe distance behind a truck -- 100 m rather than 100'.

Also for me, "properly inflated tires" means keeping my tires slightly hard at 40 PSI. The tips often say to keep your tires “properly inflated”, but the ideal pressure is usually some compromise between the figure given by your car manufacturer on the door jamb — in my car's case, 32 PSI, which is a compromise value between ride comfort and fuel economy, and what should be considered the minimum — and the max sidewall rating of the tire, 51 PSI for mine.