Projects that attempt to put things in the road tend to fail to be economical or practical. It’s almost always better putting the same (or less) investment into something equivalent that sits next to the road rather than inside it.

The key features of roads that make them so economically successful are:

1. They are very cheap per km to build
2. They are very cheap to maintain (they’re fully recyclable, they get remelted during resurfacing).

Installing anything in the road surface completely voids these two points.

Detailed problems:

• You will need a pickup device on the bottom of your car. To make it efficient you will need it as close to the road surface as possible.
• Roads are dirty and covered in debris. Your pickup device will get torn and worn.
• You will need a LOT of road installed with this, which makes it intrinsically much more expensive than roadside chargers. 10 mins of charging at a standstill requires one charger, 10 mins of charging at 40kmph is about 7km of underroad chargers. Intersections might do better, but they’re intermittent and provide unreliable charging opportunities. Even 1km (6kmph*10min) is silly expensive compared to a cluster of roadside chargers.
• The charging coils underneath the road will need to be as close to the road surface as possible (to make it efficient).
• Worn or buckled (from truck braking) road surfaces will require specialised work and extended road shutdowns to repair.
• You can’t ignore this costly maintenance: exposed electronics (even if isolated) will have inconsistent traction and may damage tires.
• Under-road assets such as communication wires (even just for traffic lights, let alone internet infrastructure), power cables (11kV and up), water, sewage, stormwater and gas will be much more expensive, slow and complicated to install and maintain. More and longer road shutdowns will result.

The fundamental, core problem of all of these “put solar panels in roads” or “put chargers in roads” projects is that they are romantically and narratively attractive. Roads are ugly wasted space, but if we could put them to better use then wouldn’t it be magic? Sadly this never works. Roads are ugly and wastes of space because nothing else works as well for transport infrastructure (other than railways).