There should be AASHTO and/or State standards for bike lanes. 3 feet is considered substandard. Most bike lanes are in the 4 to 6 foot width range; and they should be at least 5 feet wide if adjacent to a parallel parking lane, for clearance in the door zone.
IMO, if they are installing substandard width bike lanes, you should strongly emphasize safety issues and that they will be subject to liability if anyone is hurt or killed using the facility, that will get their attention.
Here's some basics from a quick google on AASHTO Bike Lane Standards (of course you will also find criticism of the AASHTO standards from John Forester and LABreform with the same google):
Space Recomendations for Bicyclists
Minimum bicycle facility width: "An operating space of 1.2 m (4 feet) is assumed as the minimum width for any facility designed for exclusive or preferential use by bicyclists. Where motor vehicle traffic volumes, motor vehicle or bicyclist speed, and the mix of truck and bus traffic increase, a more comfortable operating space of 1.5 m (5 feet) or more is desirable." Page 5
Paved shoulder minimum width: "Paved shoulders should be at least 1.2 m (4 feet) wide to accommodate bicycle travel.... Additional shoulder width is also desirable if motor vehicle speeds exceed 80 km/h (50 mph)...." Page 16
Minimum width of bike lanes, no curb and gutter: "For roadways with no curb and gutter, the minimum width of a bike lane should be 1.2 m (4 feet).... A width of 1.5 m (5 feet) or greater is preferable and additional widths are desirable where substantial truck traffic is present, or where motor vehicle speeds exceed 80 km/h (50 mph)." Pages 22-3
Minimum width of bike lanes, with curb and gutter: "(For a) bike lane along the outer portion of an urban curbed street where parking is prohibited, the recommended width of a bike lane is 1.5 m (5 feet) from the face of a curb or guardrail to the bike lane stripe. This 1.5-m (5-foot) width should be sufficient in cases where a 0.3-0.6 m (1-2 foot) wide concrete gutter pan exists...." Page 23
Bike lane/shoulder maintenance and cleaning: "Regular maintenance of bicycle lanes (and shoulders) should be a top priority, since bicyclists are unable to use a lane with potholes, debris or broken glass." Page 8
Wide curb lanes: "Wide curb lanes for bicycle use are usually preferred where shoulders are not provided, such as in restrictive urban areas. On highway sections without designated bikeways, an outside or curb lane wider than 3.6 m (12 feet) can better accommodate both bicycles and motor vehicles in the same lane and thus is beneficial to both .... In general, 4.2 m (14 feet) of usable lane width is the recommended width for shared use in a wide curb lane." Page 17
http://www.bikelib.org/roads/aashto.htm