Mitch wrote < Riding to work this morning, I noticed a new stencil on the Vilas 
Ave. pavement, right before it crosses Park St. It doesn't look like a sharrow. 
Could it be a marker to show cyclists where to go to activate a green light? If 
so, I'd like to thank whoever is responsible; I've wanted something like that 
for a long time at that intersection.>



I will pass your thanks on to the Traffic Engineers, Electricians and TE Shop 
Crew that worked on this.  Most of the signals in Madison that work via 
detection are sensitive to bicycles.  Without going into the science too 
deeply, there are loops of wire in or below the pavement with energy running 
through them that are sensitive to the movement of metal over them.  Do a web 
search on induction loop detection if you are interested in how this works.  We 
tested all of these locations with a bike with a carbon fiber frame and fork 
(alloy wheels, handlebar, stem, seat post). The area of the loop that is 
sensitive might not always be in line with where a bicyclist is generally 
operating, however.  When we receive complaints that a bicyclist was not 
detected at a traffic signal we go out to test the loop, adjust the sensitivity 
if necessary, and mark the location of greatest sensitivity.  We recently did 
this at a number of near west side locations where we had received complaints.  
Loops should have been marked at Wilson & Broom, Doty & Broom, Bedford & W 
Washington, Parr & Park, Erin & Park, Vilas & Park.  All you need to do is ride 
over the stencil, you do not need to wait on the stencil.  If anyone has other 
locations where they feel they have not been detected, please report these on 
the City's Report-A-Problem website or call Traffic Engineering at 266-4761, 
and we will check them.



Steve Arnold asked < Was it the Bicycle Detector pavement marking?

http://mutcd.fhwa.dot.gov/htm/2009/part9/fig9c_07_longdesc.htm >

I haven't been out to check these yet, but yes, this is what the stencil should 
look like.

Paul O'Leary wrote < One (well, two) of these detectors would be perfect for 
the HAWK signal at N. Blair / E. Mifflin.>
The problem is, if we installed loops here then cars would trigger the Ped/Bike 
Hybrid Beacon as well.  While we can set the sensitivity for a loop to detect 
bigger vehicles but not smaller vehicles, we can't do the reverse.  For 
example, there is a loop on Jenifer Street to detect a bus turning from the 
Jenifer Street cul-de-sac onto Williamson Street, but there is a push button 
for bicycles to trigger this signal.  We can set the sensitivity to detect a 
bus, but not a car or bicycle.  Another issue with a loop at Mifflin/Blair for 
bicyclists is that the Ped/Bike Hybrid Beacon would be triggered every time a 
bicyclist approached Blair on Mifflin.  I ride this regularly and rarely find I 
need to use this beacon at the times of day I am ride through there.

Grant Foster wrote < Parr/Park desperately needs this>
This should be marked, in both lanes.


Arthur Ross, Pedestrian-Bicycle Coordinator
City of Madison Traffic Engineering Division
215 Martin Luther King, Jr. Blvd., Suite 100
PO Box 2986
Madison, WI  53701-2986
608/266-6225

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