Two Way Left Turn Lanes
A two way left turn lane is often found in larger towns and cities running down the center of multi-lane highway. It is easily identified by the combination solid and broken yellow line at both sides and the pair of left pointing arrows painted on the road surface and displayed on black and white regulatory signs overhead. This lane may be a blessing for those who are turning left in heavy traffic, but it can make life difficult for those who wish to turn left and are entering the highway.
Road Sense for Drivers has little to say on the topic other than these lanes give left turning vehicles coming from either direction a chance to turn without holding up traffic. They can be handy for turning left in the middle of the block, such as turning into a driveway. When you use one of these lanes, remember that vehicles coming from the other direction also use this lane to turn left. Don't run into them!
If you are trying to enter a highway with a two way left turn lane by turning left onto it, you have an extra 3.5 meters or so to go, putting you at risk for a longer distance. You must travel completely across the through lanes that are coming from your left as well as the two way left turn lane before entering the first lane available for through traffic coming from your right. You cannot enter and travel along the two way left turn lane unless you intend to turn left to leave it. Similarly, one cannot stop perpendicular to the two way left turn lane inside it in order to wait for a clear spot in traffic coming from your right.
If the traffic flow is high, it may be a better decision to turn right and go around the block rather than trying to cross all of those lanes to turn left. It is farther to go, but if you are able to use a cross street with a traffic light this will safely extend your decision time and may remove a number of lanes of cross traffic from your decision making process.