This forum is about wrong numbers in science, politics and the media. It respects good science and good English.
Enginasters to the fore!
I seem to recall the late James Hunt saying of tyre pressure that the harder the tyre the faster you roll. The harder the pressure, the more sensitive to bumps and thus the need for extra smooth road surface.
This would also mean that the suspension worked less.
Seems to me that this would be a better approach, to reduce the lost energy rather than converting it.
No doubt our intrepid researcher envisions the converse, roads converted from flat surfaces to one long sequence of sleeping policemen.
But maybe there are some nice grants in this research.
I joyfully purchased a mountain bike a long time ago. It had "suspension" making the ride "smoother". I learned the first time I rode a distance further than the end of the block a simple, simple lesson. YOU DO NOT WANT suspension on your bike if you want to get somewhere efficiently. If you are going to go down a mountain, suspension is a wonderful thing. If you are pushing down on a pedal, that suspension absorbs part of your downward thrust.
The simple solution is don't have suspension...
I'm considering buying a mountain bike with front suspension. A lot of the front suspension systems now feature a "lockup" mode, where they lock themselves rigid. You can use this whilst riding on the road, then switch back to a suspension system off road.
Obviously you are still carrying around excess weight of the suspension system whilst it is locked up, and therefore wasting energy, but it's a fashion thing!
Narrower tyres would also help reduce rolling resistance. Indeed solid wheels would be even better.
As for the road surface the obvious answer would be to make all roads with an ice like surface although I would hazard a guess that some people might see a few negative attributes to such a suggestion, especially taking into account the need for globalisation of standards.
Clearly the imposition of the need for ice roads would negatively impact most of the so called "freedom of movement" rights in developing countries where the demands of the ice road creation and maintenance process would likely far exceed the national budget and power generation capabilities.
Which reminds me ....
I see Steorn is still around.