Help with custom renderer

[Majka]

Can anybody help me with custom renderer? 

I would like to visualise the roads with vehicle:conditional = no @ (from - to) tag, for example here. The processing of dates to get just the active ones might be too complicated for the renderer, so just the "simple" existence of vehicle:conditional = no or even just the presence of this tag would be fine.

The idea is to display roads closed due to roadworks. The navigation already avoids these, but I would like to see it on the map as well.

I tried to hack some custom profiles but cannot manage it.

Thanks,

Majka