Let me propose six different categories of cyclist and motorist interaction. This is a first try, so it’s open to modification.
1) Vehicular — to quote John Forester, who developed the concept of vehicular cycling, “bicyclists fare best when they act and are treated as drivers of vehicles.” In vehicular interactions, bicyclists and motorists alike use lane positions as described in the traffic law for vehicles, and reach those positions by merging. Purely vehicular operation is, however, to an extent a red herring category, because nobody, Forester included, has ever claimed that bicyclists can merge across heavy, high speed motor traffic.
2) Mostly vehicular, but with greater recognition that high-speed motoring is more compatible with bicycling if there is width for motorists to overtake without having to merge, and that bicyclists (including operators of motorized bicycles and mopeds) can’t manage to merge on roadways with high speeds and heavy traffic, making special treatments appropriate in some cases.
3) Motorists may merge across designated bike lanes. Bicyclists travel these lanes, stop for traffic lights and stop signs, but are are (in theory) not required to merge into or across motor traffic. In theory, because double-parked vehicles, people getting out of parked cars, slower bicyclists etc. often require bicyclists to merge out of a bike lane anyway.
4) Neither bicyclists nor motorists merge. They only cross each other’s paths by making crossing and turning movements at designated locations. Essentially, bicyclists are treated as pedestrians. Motorists must yield to bicyclists as they do to pedestrians, and bicyclists must slow and stop as needed so motorists have time to yield. This is the typical treatment where a designated multi-use path crosses a road.
5) Motorists must drive at pedestrian speed or come to a complete stop to avoid collisions with bicyclists they can not see, but there are special signs or markings to make motorists “aware of bicyclists”. — meaning, “aware that there might be a bicyclist.” Examples: bike lanes to the right of right turn lanes, bike boxes, blind entrances from driveways where conflict zones are indicated by colored paint, signs etc.
6) ) Motorists are required to drive at pedestrian speed or come to a complete stop to avoid collisions with bicyclists they can not see, but there are no special signs or markings to make motorists “aware of bicyclists”. Example: “shared space” plazas where direction of travel is not defined by curbs or lane lines, and traffic may travel in any direction.
These categories are in order of decreasing demands placed on bicyclists until we get to the last two, where the demands placed on motorists become excessive and so bicyclists must anticipate more motorist mistakes.
These categories also are in order of decreased efficiency of use of roadway space and of increased travel time.
As to safety, that depends on behavior, but there is a tradeoff of safety against efficiency with all of these.