Of course, with this one the state engineers may have to order the sign bridge replaced with a new, stouter one. In which case, one can have a fifteen-foot high sign with the arrows down at the bottom and away from the town names, and include the hours and days of the week when carpool are required.
And so I created one.
The arrows are rightly positioned in their lanes. The overhead directional signs above the arrowboard correctly identify which lanes will go where (right lane arrow, McCarthy Blvd or East 237 Calaveras Blvd Milpitas only, centre-right arrow either 237 or 680, centre-left arrow 680, left arrow 680 Express lane). While not perfect, the sign is legible enough to guide the motorists where they need to go.
And I got the hours on the microscopic HOV 2+ carpools only sign right, too!