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Buried traffic detection loops.
Bike triggering problems.
Applicable to all motorcycles, and even some sidecar rigs.

Copyright 2018, R. Fleischer

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The most common in-road vehicle detector is a loop of buried wire, often located just before any crosswalk or traffic signal area.   These "loops" can be rectangular, round, Z-shaped, can be in multiple loops, and also strangely shaped, etc.  In some instances, these detectors are located well before any traffic signal light, or even multiple ones in any given traffic lane, and even at freeway off-ramps.

These detection loops may be buried with no indication of where they are located, or you might see slits, repair areas,  painted marks, or even a motorcycle symbol.  If a motorcycle symbol, that area is supposedly where your motorcycle, over it, is most likely going to trigger the traffic light.  The traffic signal MAY be set up to allow a full cycle of opposing traffic, before YOUR direction is changed to a green light.  This is a delay purposely built into the system.

PURPOSE: Obviously the purpose of these buried loops is to control traffic; safely and orderly; specifically, the loops are there to enable the traffic control signal to detect vehicles, and, one hopes, detect smaller vehicles, such as motorcycles, which have less metal that could be detected, versus cars, trucks, etc.

The loops are almost always NOT sensitive to external magnetic fields (those $$ magnets you can purchase are pretty much worthless); but they ARE sensitive to the size, and somewhat sensitive to the mass, of any METAL, located in proximity.   There is an alternating current in the loop(s), and the magnetic field produced is sensitive to being 'disturbed' by nearby metal (YOUR BIKE!); and that sensitivity (like a metal detector operates) triggers the traffic light electronics in the manner designed-for (delays, order of events, whatever).   These types of loop electronics are sometimes used to trigger metal or wood gates at certain types of crossings.


Every State in the USA has vehicle laws that cover problems with inoperative or wrongly operating signal lights.  These laws vary, sometimes considerably.  In my home State of California, problems with these are covered under Vehicle Code Section 21800, Intersections. While there is more to the 21800 section, the following is the pertinent part, which may be similar in YOUR State, or one you are traveling in:

CVC 21800(d)(1):    "The driver of any vehicle approaching an intersection which has official traffic control signals that are inoperative shall stop at the intersection, and may proceed with caution when it is safe to do so."  "Inoperative" also includes wrongly operating. 

If the loop does not trigger from your motorcycle, it is considered inoperative.  There are adjustments for sensitivity.  The sensitivity must be adjusted by the traffic signal maintenance department having that responsibility.

If you want any particularly traffic signal to be repaired or adjusted, it is up to you to find out who has responsibility, and to report the problems to them, in detail.    I suggest you NOT initially try to telephone them; NOR, E-mail them; although your could do both of those, if you wanted-to.   I DO suggest you write a real letter, you know, typed or printed on paper ...and prominently display at the bottom of the letter that carbon copies are being sent to other Authorities; and list them at the bottom.

Entities that might be controlling are such as the following.  Address to one, CC to all the others:
State or County Highway Departments.
State, County, or local Departments of Transportation.
Traffic Enforcement; Police; Sheriff, etc.
Department of Safety.

It has been suggested that the best way to get a response ...and a fix! to have the letter(s) done as above; AND, that the letter contains the DETAILS, the details being explained in such a way that these various authorities might think seriously about lawsuits, bad publicity over an accident, ETC.,  if this traffic signal is not repaired.  Be polite.  You want the letter to INCLUDE:

1.  The description of the intersection or street; what are the names of the road(s), etc.
2.  The exact corner and lane, by exact description ...including direction of travel, exactly.
3.  That you have repeatedly tried different positions to trigger the signal using a motorcycle.
4.  After the light cycles 2 times failing to trigger – you have been carefully looking each way and ride through the intersection, but you consider the failure for the signal to operate is dangerous.  ((side note:  keep a copy of the letter pointing this particular reason, is that if YOU received a citation for going through a red light after a full stop, etc, it will influence the Judge, in any Court appearance, to drop the matter. Remember:  A moving violation will affect your insurance rates!!

I suggest you do NOT fail to include 5.

04/14/2016:  Metas updated, article cleaned up slightly.
12/23/2016:  Update metas and scripts.  Add one H.L.  Go through article; clean up, and clean up HTML.
05/15/2018:  Cleanup, reduce HTML, slight layout improvements and add 10pxl margins.

Copyright 2018, R. Fleischer

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Last edit of THIS page: Saturday, December 05, 2020