Two solid yellow lines down the middle of the road mean:

Double solid yellow lines (two solid yellow lines side by side) prohibit passing in both directions. The line marks a section of road where sight distance, curve, hill, or intersection density makes passing unsafe regardless of which direction you are going. You may not cross double yellow lines to pass another vehicle, even if the oncoming lane appears clear. You may cross briefly for turns into driveways or side streets where this is permitted, and some states allow crossing to overtake bicycles when safe. One solid and one broken yellow line means passing is permitted from the side with the broken line, prohibited from the side with the solid line — passing rules apply only to your side.