In Southern CA, the HOV (High Occupancy Vehicle or Carpool Lanes) are setup with double yellow lines and intermittent breaking white lines which allow for entry and exit. You can only enter and exit carpool lanes during these breaks.

Why restrict when drivers can enter and exit? Who cares when a driver with multiple passengers enters or exits the carpool lane? How is it any different from someone using the lane next to them to pass? If anything, these restrictions add angst to drivers who worry whether they will legally be able to exit the carpool lane before their exit. The rule should be simple: you can enter or exit a HOV lane if you qualify to be in the lane. If you have enough passengers, then use it as you wish. If you don't, you cannot use it under any circumstances barring an emergency. CA spend millions on painting double yellow and in some cases quadruple yellow lines for the perceived worry that cars might use it for a passing lane which ought to be treated no different than any other lane.

By contrast, the Bay Area is far more intelligent about carpool lanes. Their carpool lanes allow for entry and exit by qualifying vehicles whenever they wish. In many cases, they also have time limits on the HOV lanes so that if it is the middle of the day on a Saturday for example, anyone can use the HOV lane.

The second problem with carpool lanes is that their primary purpose is not being served. The primary reason for HOV lanes was to encourage people to carpool and take drivers off the road thus easing conjestion. However, in no way does it serve this purpose if the other passengers are not legally permitted to drive. In other words, the rule should be two or more licensed drivers not just passengers. Thus, soccer moms ferreting their minions should not qualify for the carpool lane.