From the point of view of generating electricity from solar power, this bike lane in the median of a busy Korean highway seems to be a good idea. With solar power, there is some concern about where to locate the solar panels if there are not rooftops available, because land can be very expensive depending on the location. Also, people need land for recreation and agriculture, and animals need it for habitat.
Placing solar panels in the median of a highway seems perfectly acceptable because that space is not likely to be used in a way that would be better. It also is a good location because it shows that solar power can be integrated into everyday life just about anywhere there is enough sunlight. Due to the dramatic decrease in their cost, we might begin to see them just about anywhere.
It also is sensible to have bike lanes on level ground with gradual inclines and declines, because cyclists can manage such hills much easier than the steeper ones. Highways can also be very direct routes between cities, so bicyclists can have shorter trips.
Someone made a video showing the panel-covered bike lane, using a drone with a video camera (video above).
The potential problems for cyclists using the lane would be exposure to air pollution, which might cause cancer, respiratory illness, or heart disease. One way to reduce this exposure, at least somewhat, would be to only bike when there is less traffic. So, it might not be a good idea to bike there during rush hour. Imagine going out early Sunday morning when there are not many cars or trucks on the highway. Traffic might be lower on some holidays too. Also, as more hybrid and electric vehicles are manufactured and purchased, air pollution should decrease a great deal. Eventually, all vehicles might be electric, which means there would be no tailpipe emissions and none of the vehicle air pollution we experience today.
Another potential hazard mentioned by online commenters is the possibility of vehicles crashing through barriers and injuring or killing cyclists. This contingency is possible, but has it happened? Are there any confirmed accidents or is this more of a fearmongering, catastrophizing question?