Originally Posted by turbo1889

^ Exactly, just as the vast majority of regular automobile vehicle travel lanes need to be planned and built to accommodate not just regular cars but also heavier, wider, and longer cargo trucks including 18-wheel rigs. Bike vehicle lanes also need to be planned and built to accommodate not just regular two wheel in-line bicycles but also trikes, quads, etc . . . of reasonable width.

We could argue as to what is and is not reasonable width but to my mind 4' width is plenty and is already an established standard for golf carts and most ATV ranch vehicles (John Deer 4x6 Gator for example). A normal bicycle with a normal single rider takes up about 2.5' of width or so depending on the rider and the handlebar style used and how wide the riders arms are positioned are as a result. An extra 1.5' isn't a whole lot extra to ask to accommodate a larger array of cycle vehicles.

For automobile vehicles 5'-7' width is normal, but heavy cargo trucks, buses, motor-homes, etc. . . the width jumps up to 8'-9' and "Wide Load" tractor trailer rigs can run even wider, up to 12' width without requiring a special permit and only needing a pilot warning vehicle front and rear with the proper signage. No reason why pedal cycle vehicles wouldn't follow a similar pattern approximately 2.5' width for normal cycles and up to 4' for the wider ones. Seems reasonable enough to me and basically the same pattern.