Question

the road bridges and parks that we use are called public property what is the reason behind it

Answer 1

because it is not owned by any individual or a community
it is owned by government and can be used by everyone

Answer 2

as it is common for all the citizens for their use and enjoyment . it is not meant specially for any person . it can be used equally by every citizen and and it is by the government for the public . therefore it is known as public property .