What do double solid white lines separating traffic lanes mean?
Correct answer: B – You must not cross them to change lanes
The Texas Driver Handbook states that crossing double solid white pavement lines is prohibited. These lines may be used to separate lanes where drivers must remain in their current lane. They do not mark a center turn lane or give permission to cross for passing.
Source: Texas Driver Handbook — Ch. 5, “Solid Lines”, 2025 Texas Manual on Uniform Traffic Control Devices — Fig. 3B-8, “Example of Double Solid White Line Used to Prohibit Lane Changing”





