I really think you're making it sound like the turbines is going to make cars less efficient in some appreciable manner.
I dunno a lot about aerodynamics.. just basic stuff really.
But, I think anyone is going to be hard pressed to display that a series of turbines wrapped around existing hardware along the side of any major arterial road is going to seriously affect the drag coefficient of those cars, and therefore their respective 'energy usage'.
1/. the existing hardware is already the culprit in causing drag on these cars. Again, I doubt that this drag is in any way significant  .. but as I said, I'm not an aero engineer, so not in a position to calculate this .. so for sure doubt my ramblings.
2/. there is almost certainly going to be other fixtures and fittings along these major arterial roads too .. eg massive signposts, fencing(ie. safety fencing) and whatever other drag reducing fixtures that you generally see on the side of all major roads.
3/. I have never personally experienced any difference in fuel usage due to drag caused by roadside hardware causing significant aero drag having driven many millions of kilometers. Hundreds of klms driven on a major city freeway or desolate backroad .. I rarely see any difference driven pretty much consistently. 
4/. vehicles are not really expected to get much more aero in the forseeable future, and as I understand aero(very basically remember), the major problem with making cars too slippery is that they also become unstable in variable conditions. So any further reduction in drag coefficients in future models of cars should see negligible effects on fuel usage by the turbine installations.
5/. reminder that these things are wind turbines too .. ie. they don't even need vehicles passing by to generate their power .. light winds also get them generating. 
6/. if there was only a single vehicle ever!... in any part of the world at any one time .. ie. we didnt' have the insane levels of traffic that predominate the urban landscape, maybe your argument could have some merit.
But my (basic, again) interpretation of the system is that traffic is creating the draft/turbulence that get these turbines generating. So that as a vehicle is passing by, the generator is already moving(ie. has momentum) and the next vehicle is 'assisting' the turbine to keep up it's momentum. ie. in normal traffic the drag effect of a turbine ON the next passing vehicle is even more diminished. 
7/. if fuel miserly-ness is a major concern for you, maybe take up a cause that WILL actually make a difference. From observation of 12 hr days on the road pretty much most days of the week .. I reckon at least half the cars and trucks on the road drive with underinflated tyres. A far bigger impact on fuel use on a vehicle, than a thousandth of a percent of increased drag on already quite efficient regular vehicle.
To knock this idea on it's head, before it's even trialled/tested .. sounds alarmingly short sighted.
About the only real criticism that would crop up with this idea, as always seems to happen .. is the actual cost/benefit performance. Will it be what is claimed by the company. 
But from my earlier comment about observing traffic(and many vehicles with low tyre pressure(s) ... this turbine idea would work an absolute treat on our(Melbourne's) Ring Road. This road(if anyone knows it) .. is trafficked pretty much 24/7(primarily the 30 or so klms from it's south to the Hume Freeway).
				
			 
			
		 
			
				
			
			
				Arthur.
All these discos are giving me a heart attack!
'99 D1 300Tdi Auto ( now sold :( )
'03 D2 Td5 Auto
'03 D2a Td5 Auto
			
			
		 
	
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