You know, the document that every pimply faced teenager reads and must understand before successfully completing the drivers test? Without further ado [commentary in brackets]...
Sharing the Road with Bicycles
Bicycle Rules for Motorists
1. A bicycle is a vehicle and any person riding a bicycle has all of the rights and responsibilities as a driver of a vehicle.
2. Bicyclists are required to ride as far to the right as possible only when the lane can be safely shared by a car and a bicycle, side by side [i.e. when the lane is wider than 14']. Even then, there are certain conditions that allow a bicyclist to take the full lane such as:
a. The person is overtaking and passing another vehicle proceeding in the same direction [In heavy traffic, this does happen from time to time, especially around city busses that make frequent stops]
b. The person is preparing for a left turn at an intersection or onto a private road or driveway
c. There are unsafe conditions in the roadway such as fixed or moving objects, parked or moving vehicles, pedestrians, animals, potholes, or debris [It's like they wrote this one with Dallas in mind...]
d. The lane is of substandard width [which describes the majority of roads in and around downtown Dallas] making it unsafe for a car and a bicycle to safely share the lane side by side. When this is the case, it is best for the cyclist to take the full lane whether riding single file or two abreast.
3. Bicyclists are not restricted to the right lane of traffic. One-way, multilaned streets are one example. Another instance is when the bicyclist is changing lanes to make a left turn. The bicyclist should follow the same path any other vehicle would take traveling in the same direction.
4. Motorists should merge with bicycle traffic when preparing for a right hand turn. Avoid turning directly across the path of bicycle traffic.
As you can see, it's right there in the drivers handbook, page 9-7, link is here:
Don't tell me you had forgotten about this already?