is it better to go with the flow on the hwy?

[MetroMPG]

The question stands: Is less fuel consumed overall if you speed to keep up with traffic instead of driving the speed limit when everyone around you is speeding? Need someone with statistics on that one.

it's an interesting question actually.

the stretch of 4-lane freeway that passes thru my neck of the woods has a limit of 100km/h. there is almost always a service road or 2-lane hwy that parallels it with a limit of 80k.

if i'm just tooling around i normally opt to drive on the 80k road at or slightly above the limit, rather than on the freeway where my chosen speed is usually below the average of traffic.

but having said that, i have noticed once or twice that after merging from the 80kph hwy onto the 100kph freeway into a steady flow of traffic, my average fuel consumption reading has started to climb.

i haven't tested this - it's just an observation i've made maybe 2 or 3 times. it suggests aerodynamic factors at play, and maybe in a certain density of traffic, you're better off going with the flow to take advantage of this effect.

the questions are what speed? what density? i don't know. hard to test in controlled conditions, too.

and i should point out that i don't tailgate - at hwy speeds i'm usually 3 seconds or more from the car ahead.

if you doubt the possibility of a stream of traffic significantly altering the flow of air on (or near) a roadway, you just have to stand beside one for a few seconds.

...or look at this college project to generate electricity by putting wind turbines next to a busy stretch of toronto highway: Tapping the Wind Force of Traffic