I wish you could control when to place signals and when not to. The game's inbuilt "fast Lanes" highway system is very boring and doesn't allow lots of customization. You can work around that by using expressways and large avenues converted to one way but if you want to make and exit from the highway it forms a signal. Also they should reduce the minimum angle for road formation. If they can't do this something like a Rural Highway Mod for SimCity would be amazing as this allows for ultimate, realistic, customization.