"Sometimes you can found that there are some giant thing getting transport around in your city, prepare the roads for them and receive your extra income!"
This policies will boost your factory efficiency, prone to export to outside connection and boost population trend in your city. Sometimes they will sent them to your local high dens commercial, marketplace (signature buildings) and factories from signature buildings tab. So road planning will more important.
During this event happening, some roads that too small will closed for the transport. And when transport was finished, they gonna post their result in Chirper.
There are downside too
-They can't drive on Alley/Gravel road if that road have any building built beside.
-They need to drive on Large road (or at least 3 lanes road) due they're 1.5 lane wide so they need to use 2 lane to drive on otherwise they need to temporary close the road.
-Road wear will higher than normal in their path.
-They slow