Two lanes each way promotes faster driving except when someone must turn left into a business. That vehicle must then stop in the left lane to await a break in two lanes of oncoming traffic. Following vehicles must wait or change lanes. Right turning vehicles block the right lane until they have completed their exit.
A single lane each way with a centre left turn lane and bike lanes on either side promotes a slightly slower speed but much steadier flow. Left-turning vehicles quickly clear the drive lane by moving into the left turn lane. Right-turning vehicles more quickly clear the drive lane due to the width of the bike lane.
Although the centre left turn lane and the two bike lanes may at first glimpse appear to be wasted space, they function to keep the drive lanes unimpeded.
In summary, the double lane configuration will carry the most traffic, providing it is through traffic. Single, unimpeded lanes will carry nearly as much traffic and provide ready access to businesses on either side.
Al Johnson, Vernon