What is the ruling on building a balcony extending about 80 centimeters over the road on the upper floor, beyond the boundaries of the owned land?

It is forbidden to place anything that obstructs public roads because they are a common good for everyone, and such an act could lead to harm and corruption. Some scholars have absolutely prohibited this, regardless of whether harm results or not, as a way of blocking the means that could constrict people and cause them damage.