How can you distinguish a reversible lane from a shared center left-turn lane by markings and controls?

1. Both lanes are marked only with blue service signs
2. A shared center turn lane always has a red X overhead
3. Reversible lanes are usually double-broken yellow with signs or overhead lights; shared center turn lanes use alternating left-turn arrows and solid/broken yellow lines on both sides
4. A reversible lane is always marked with a white crosswalk