LMTVs and Traffic Signal Actuators

[aleigh]

Of all the things - my 1078 seems to have problems tripping traffic signal actuators like at left turns - at least around the Phoenix area. This seems counter-intuitive since the thing has a curb weight of 17 grand, but, it's happened to me a couple of times now at two different lights resulting in me eventually having to blow the red. Too high to trip the actuator? And yes, I know what & where the things in the pavement are.

Anyone else had this experience? I'm sure the cop who eventually sees me doing it isn't going to believe me.

 

[Scar59]

It happens, the sensors are no longer weight sensitive, they are electro magnetic sensitive. Truck is to high off the ground. Motorcycles have the same concern, bike has to stop right over the sense element, stop in the middle of the lane and you'll have to blow the red.

 

[bikeman]

Yep, even happens on base. HEMMTS and the FMTVs are too tall. You can hang some chains along your axles or similar that are lower and (hopefully) activate. The other thing to do is look up your state laws, regarding motorcycles, and how they are to use the actuators. Follow the same guidelines and explain to the LEO if you get pulled over what's up.

 

[aleigh]

Yeah back home in WA you have sit out two cycles on your motorcycle and then you can blow it. (I ride motorcycles). I don't know what the deal is down here in AZ. Either way I foresee explaining to cops sooner or later. Sigh. Time to print out more regulations to keep in the truck (along with why-i-dont-have-a-dot-number).

 

[Oxyacetylene]

Happens to me all the time. Now on the common routes I drive, if a passenger car is not already in the turning lane waiting, then I take a right instead and go a different way, when it's practical anyway. If there are double left turning lanes, I make sure to get in the lane with at least one car already waiting. Sometimes I do just have to run the light...which makes you look bad when the passenger car behind you then eases up to the line and the light turns!

 

[jasonjc]

Lights are going to video so this does now happen as often.

 

[Keith Knight]

I've been installing those "sensors" for over ten years in the electric gate business I owned. The the part you see in the ground that is commonly rectangular in shape but can be in many shapes is actually just insulated copper wire that makes a loop around that shape multiple times depending on the size of the shape. The the larger the shape the fewer the loops around the smaller shapes have more loops. Then from the shape the wire is twisted to cancel the signal back to the control box where the wires are connected to the loop detector. The loop detector turns the wires out in the road, that are in the rectangular shape into a type of antenna which when a metallic object disturbs the field it triggers an action. The larger the shape the higher it can detect. Our standard shape is 6'x6' and could detect up to 3' above the asphalt a 10'x 10' could in theory detect up to 5' above the asphalt. But a 6'x12' could only detect up to 3' above the asphalt but would have a longer area in the lane of detection. Note: It not only detects up but 3' left and right of the wires in the ground so the weakest area for detection is in the middle of the loop or to far to the left, right, front or back.
Hopefully that helps everyone understand how they work a little more.
Now for the important part! How do you make sure it reads your vehicle.
If you can see the where they cut the wires into the road, for large / tall trucks try stopping so your axle is directly over the front of the loop or the back of the loop so that your axle is as close as possible the the wires. For motorcycles try stopping directly over the left or right side of the loop. If you can't see it then it's guess work but try going a light forward or backwards. For motorcycles in a 12' wide lane the left it right side is going to be about 3' from the yellow or white lines so it won't detect vehicles in the lanes next to it.
Good luck!