Encourage carpooling. Sign explicitly states the rules for accessing the HOV lane. Reward environmentally friendly behavior with a sign that works!
Guidance: 01 The Preferential Lane Advance (R3-12, R3-12f, R3-15, and R3-15d) signs should be used for advance notification of a barrier-separated, buffer-separated, or contiguous preferential lane that is added to the general-purpose lanes. 02 The Preferential Lane Advance (R3-12e and R3-15a) signs should be used for advance notification of a general-purpose lane that becomes a preferential lane.