How narrow is the bike lane? Any pictures? Maybe a google maps street view? There's a bike lane in my town that narrows down to 6" to the left of the gutter pan at one point. I usually move out of and take the lane there. Since the bike lane doesn't conform with the California MUTCD it's in violation of the California streets & highways code and legally is not a bike lane. You may want to become a "would be traffic law scholar" as some around here might say and look up your local laws. Here's the streets & highway codes I'm thinking of (for california...found at leginfo.ca.gov)
890.6. The department, in cooperation with county and city
governments, shall establish minimum safety design criteria for the
planning and construction of bikeways and roadways where bicycle
travel is permitted. The criteria shall include, but not be limited
to, the design speed of the facility, minimum widths and clearances,
grade, radius of curvature, pavement surface, actuation of automatic
traffic control devices, drainage, and general safety. The criteria
shall be updated biennially, or more often, as needed.
890.8. The department shall establish uniform specifications and
symbols for signs, markers, and traffic control devices to designate
bikeways, regulate traffic, improve safety and convenience for
bicyclists, and alert pedestrians and motorists of the presence of
bicyclists on bikeways and on roadways where bicycle travel is
permitted.
891. All city, county, regional, and other local agencies
responsible for the development or operation of bikeways or roadways
where bicycle travel is permitted shall utilize all minimum safety
design criteria and uniform specifications and symbols for signs,.
markers, and traffic control devices established pursuant to Sections
890.6 and 890.8.
I'm assuming the "criteria" mentioned are those in the California MUTCD, which states that a bike lane stripe should be a minimum of 3 feet from the gutter pan, or 4 feet from the curb if the gutter pan is more than 1 foot wide. see here:
http://www.dot.ca.gov/hq/traffops/si...UTCD-Part9.pdf (caution: this is a 3+mb PDF file)