Solar roadways are most effective when not used as roadways.
The hexagons have about 50% active solar panel area.
Traffic, whether pedestrian, cyclist or vehicular throws shadows.
Shadows have greater area the further North or South from the equator.
Shadows consist of umbra and penumbra, so the shadow area is always greater than the geometrically projected area of the object casting the shadow.
Any single cell in a series which is shadowed acts as a resistance to all the other cells, rather like an aged battery in series with new ones.
Road panels are laid flat. The further from the equator the lower the efficiency.
A better design: An open-sided shelter.
Solar panels should be placed above the road, forming a roof.
The side towards the prevailing wind should consist of open mesh or louvres. The other side is best left open.
The panels are fixed, oriented to about 12 local time and midway between local max and min zenith angle. This makes for a simple design with no need for motors to move the panels.
The open mesh or louvred side will actively reduce the impact of wind, rain or snow on road users.
The streetview image linked below shows how the Swale crossing and the louvres keep rain off the ground to such an extent that the soil is bare of plants.
Swale crossingI am currently installing solar panels in my garden to power my fridge. I can confirm by direct experiment that if a part of a panel is in shadow, then the whole panel acts as if in shadow: the power drop is significant.