I've had 35% tint on the windshield of multiple vehicles over the last 10 years in NM, TX, NC, and now CO. Never once had an issue with law enforcement.
Before someone asks "Why would you tint the windshield?" I'll explain. With the 35% on the windshield my vehicle's interior is greatly protected from the sun's heat. I also never have to use the visor in my truck. If the sun is low and I'm facing it head on, a pair of sunglasses + the tint are adequate shading for me to drive comfortably. No, I do not have any issues seeing at night. If I had old, dim headlights then yes, it would probably be a concern.