The Bicycle Detector Pavement Marking (CA-MUTCD Figure 9C-7, shown at right) is placed to show a bicyclist where to stop so that they can trigger a traffic signal. When installed properly, they prevent the all-too-common scenario where bicyclists cannot trigger signals and must either cross against the red light when a safe gap is available, or wait until a motor vehicle arrives. They are also a clear signal to motorists that there is a reason why the bicyclist is positioned where they are. Of course “bicycles may use full lane” is true approaching any intersection where right turns are permitted, however, most motorists do not know or remember this law unless there is a sign there to remind them. The sharrow serves a similar purpose. However, these markings are often not installed in properly.
Here is another fresh Sacramento County mistake, where the marking was not placed properly. On Mission Ave southbound, approaching Marconi Ave, there is a Bicycle Detector Pavement Marking in the bike lane, but not in the regular through/right turn lane. This marking is on new pavement placed in a complete streets project along Marconi from Mission westward to Fulton, and was installed within the last two years. If a bicyclist is to trigger the signal, they have to stay in the right hand edge bicycle lane, where they are at risk of getting right hooked. If they adopt a merge position between the two lanes, where they should be in order to make clear to motor vehicle drivers to either get in front or fall in behind, not beside, then the signal won’t trigger.
The solution is to place a marker in the regular lane, and adjust loop sensitivity if necessary, so that the bicyclist can choose which lane position to use.