asked: What is the minimum road width that allows a bike
In other words is a 15 foot lane width or a 12 foot lane width enough to allow a 5 foot bike lane to be incorporated within it?
I’m afraid the answer is not as simple as the question implies and I cannot give a comprehensive answer. Roadway design is complex and dependent on numerous factors, including proximity to urban centers, travel volumes and whether the roadway is new construction or rehabilitation. The following is some information from the FDOT Plans Preparation Manual.
8.4.1 Bicycle Lanes
Where required by Table 8.1.1, provide a bicycle lane for each direction of travel on the roadway. The bicycle lane is defined as the area between the edge of travel lane and the edge of pavement. Bicycle lanes are to be marked in accordance with Design Standards, Index 17347 and the MUTCD. Shared use paths do not meet the requirement for bicycle lanes. For new construction or reconstruction projects, both curbed and flush shoulder roadways, the standard width of a buffered bicycle lane is 7 feet. For high-speed curbed arterials, the standard width of a buffered bicycle lane is 6.5 feet.
For RRR projects, the distribution of available roadway width may require a bicycle lane other than the standard buffered bicycle lane (refer to Section 220.127.116.11 of this Volume). When providing a bicycle lane on a RRR project, the options in the order of priority are:
1. 7-foot buffered bicycle lane
2. 6-foot buffered bicycle lane
3. 5-foot conventional bicycle lane
4. 4-foot conventional bicycle lane
Traffic Lanes are typically 10 to 12 feet wide depending on many factors. A 15-foot wide curb lane is normally shared by many types of vehicles.
27. Traffic Lane/Traveled Way: The designated widths of roadway pavement, exclusive of shoulders and bicycle lanes, marked to separate opposing traffic or vehicles traveling in the same direction. Traffic lanes include through travel lanes, auxiliary lanes, turn lanes, weaving, passing, and climbing lanes. They provide space for passenger cars, trucks, buses, recreational vehicles and, in some cases, bicycles.
You can find more information about bicycle facilities here. You may need to copy and paste into your browser: