Q. Good day,
I am a member of the Mississauga Cycling Advisory  Committee in Mississauga, Ontario, Canada. We are volunteers that promote cycling of all types in our fair city and advise city concillours on cycling issues. I was wondering what you think of the possibility to extend the traffic signal loop detector from detecting bikes at a stand-still, to detecting bicycles in motion on a bike lane while approaching an intersection.

Let me explain:In order to encourage more people to cycle instead of taking their motor vehicles in our sub-urban city, I want to explore priority traffic signals for oncoming cyclists. This would give a much greater chance of the bicycle receiving a green signal at a safe, calculated distance – allowing the cyclist to stay in motion while cycling straight through the intersection.

It would look something like this:
- Put a loop detector in the right-hand bike lane about 40-50 metres (approx 50 yards) from the intersection.
- This loop should detect a bicycle riding over it at normal cycling speeds
- When a moving bicycle is detected, the traffic light will advance to a green light for the
oncoming bicycle.

Benefits & Considerations:
- If an unexpectedly large number of cyclists took to the street, they may find themselves waiting about the same as motor traffic. Perhaps priorities can be set between north-south and east-west traffic?
- Motorists would catch on to this and try to (illegally) drive over the bike signal as they approach. To avoid this, place road bump barriers as a deterance to motorists crossing into the bike lane near that location.
- The detector location should be marked on the road.
- The loop detector must be far enough back to allow the cyclist to pull out of the bike lane to overtake/pass vehicles making right-hand turns.
- If motorists view the efficiency of cycling through that route then they will be encouraged
to using a bicycle instead of a motor vehicle for some of their motor trips.
- “If you were on your bicycle, you would be home by now”
- The goal is not to take away the flow of motor traffic, yet to still make it more fluid for cyclists. I.e. Reward cyclists without harshly punishing motor vehicle drivers.
- This would be far less expensive to implement than putting in, say, a bicycle freeway.

I would love to hear your thoughts on this.
Allan Harder
MCAC Member
http://www.mississaugacycling.ca

A. Hi Allan–
Off hand, I don’t see a big difference — in terms of wiring — between an advance loop for motor vehicles (pretty common practice) and an advance loop for bicycles. The biggest concerns, I think, would be if there is adequate capacity in the electronics to add a new circuit and if the loop design will detect bicycles reasonably well (the best designs, if memory serves, are the quadrupole or diagonal quadrupole). Come to think of it, even a simple rectangle loop should work if its sensitivity can be adjusted separately from, say, motor vehicle detectors. Which should be the case. An advance loop could also alert the system to an approaching bicyclist, so that the bicyclist might get the green sooner.

I’ve forwarded your inquiry to several bicycle traffic engineering experts who undoubtedly have
significantly more insight than I do on the subject.  I’ll let you know what I hear back.

Cheers!
John W.

A. Allan has a pretty good grip on this except for the physical barrier between motor vehicles and bicycles. A barrier of this nature is one that a bicyclist could “crash and burn” on! It is really quite unnecessary anyway as motorists wouldn’t understand the nuances of bicycle detection and signal timing! I’m sending you both a copy of an article I wrote about a detection system that I implemented in the City of Cupertino way back in 1977. Yep, more than  thirty (30) years ago. You don’t need to do exactly as I have done, however, this should give you concepts that you can build upon.
Glenn

 

Jean-Francois Rheault wrote:
We manufacture loops for bike lanes that do not register motorized traffic. The system has been designed for counting but can be hooked up to traffic signal for detection.

Jean-Francois Rheault
Eco-counter – Bike / Ped counters
<http://www.eco-compteur.com>www.eco-counter.com
Canada & USA: 1-866-518-4404 (toll free)

Eco-counter on video: <http://www.youtube.com/watch?v=PtyxloPoyI8>

 
Bob Shanteau wrote:
As far as inductive loop detection of bicycles, bike lane or not, see:

<http://rmshant.googlepages.com/DetectingBicyclesandMotorVehiclesUsi.pdf>
<http://rmshant.googlepages.com/BicycleDetectionatTrafficActuatedSig.pdf>

Also Kelly Hughes just called me from New Zealand to tell me about his company’s induction pads that can be used in bike lanes, as long as not too many motor vehicles pass over them:

<http://www.advancedtrafficsupplies.com/detail_xflo.html>

 

Theo Petritsch added:
Sounds like a groovy idea if you can sell it to the local Traffic Ops folks.If they go for it, more power to you.It may be an easier sell to start at the other end of the green. Our MUTCD
requires that:

“On bikeways, signal timing and actuation shall be reviewed and adjusted to consider the needs of bicyclists.”

In addition to (possibly) extending the minimum green time, this could also apply to extending the green time to allow an approaching bicyclist to clear the intersection prior to the red. Basically the dilemma zone can be calculated and loops placed to ensure that a bicyclists traveling at a given speed is not required to stop.

While I like your idea for its high visibility to motorists and bicyclists, my modification may be easier to sell. Extension of the green to prevent the signal trap for cyclists is just a more comprehensive application of an already common treatment. Preemption is typically used for emergency vehicles – in which case the preemption is usually on demand and immediate allowing just for the clearance interval on the side street; or it is used for transit, in which case the minimum side street green times and clearance intervals are maintained – reducing but not eliminating the potential for busses having to stop.

 

While at most intersections, the 10 to 13 second advance notice provided by a 50 m advanced loop would mean the side street would still have plenty of time for a minimum green and clearance, some area have intersections so large that this may not be adequate. Sneaker left turns at the end of a cycle have also caused concerns for advancing the green types of preemption. I think those concerns would be minimal in areas with smaller intersections.

Hope any of this was useful.

Theodore A. Petritsch, P.E., PTOE
Senior Transportation Engineer
 Sprinkle Consulting, Inc.
tap@sprinkleconsulting.com