I know that the window tint is not supposed to be less than 70% light transmission on the side windows per the FMCSA. http://www.fmcsa.dot.gov/regulations/title49/section/393.60 On our dump trucks we adhere to this. However I have a dually pickup that is only under FMCSA when I am pulling a trailer which about 25% of the time. I am considering tinting the windows to the 25% state allowed limit as this Texas sun is brutal. I know I will be in violation when towing but I am considering taking that chance. Just curious what the penalties, points, consequences are. Is it just a fine or are there more serious implications? For what it is worth I had 25% tinted windows on my last pickup and was stopped but the DOT three times for weight check and they never asked about the windows. Maybe I just got lucky.