State funds are usually derived from gas taxes, making transportation budgets at least generally predictable. Federal Highway Administration funding comprises a large chunk of the money for road and bridge projects. With those funds come federal requirements. Each state transportation agency must write a Transportation Improvement Program, comprised of the plans from smaller regional planning organizations. Public involvement, crucial for all capital projects, is required by the feds for transportation.
Most states do a good job here, and some have even found room for innovation.
Arizona surveys its state's drivers, and Missouri officials conduct focus groups while driving the highways. Considering that transportation projects often account for the bulk of a state's capital program, making sure the public is on board is a good idea. Of course, the current good times aren't going to roll on forever. And as any capital manager will tell you, this province is often the first one cut when the economy turns south. Road maintenance can be ignored for years before Volkswagens start falling into potholes.