Praise be to Allah.
I put this question to our shaykh, ‘Abd ar-Rahman al-Barrak (may Allah, may He be exalted, preserve him), and he replied:
It is not permissible for you to do that, even if it does not constrict the road or affect passers-by, because the road is public property and belongs to everyone, so it is not permissible to transgress or encroach on it. End quote.
And Allah knows best.