Is it important that they started with bike lanes and not full roadways? A bicycle vs. a delivery truck present radically different loads to the roadway.
The road is much wider, and pose greater disruption to transport during installation - If the experiment fails because it can't even take bicycle loads, and bicycle wear and tear, there would be bigger waste. If 70m works (physically, politically, economically), do 100m. If 100m works, go for 500m. If that works, do a 50m prototype on a road. Something like that.
It would also be far more costly. As roadways have way higher requirements then bikes.