City planners help do the big roads, and plan where residential vs commercial property will be. Inside of communities the developer decides, gets it approved by the local government, and then many times gidts the roads back to the city after the subdivision is built. Sometimes they stay private roads.
In America the interstate system has a lot of logic to it. Odd numbers run north south (I95) and evens run east west (I10). The north south are lowest numbers in the west getting bigger and bigger going east. So, I75 is west of I95. I10 is south of I40.
Sometimes land is take through eminent domain, which means the government takes the land from property owners. They pay the owners, but many times this is met with a lot of resistance from owners and local communities. People can fight the government andnplans for roads, and sometimes they win.