# Traffic signals not sensing my hybrid. Is this possible? **URL:** \ **Category:** Factual Questions\ **Created:** [August 31, 2012, 3:42pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268 "2012-08-31T15:42:53Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [September 1, 2012, 1:44am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/21 "2012-09-01T01:44:05Z")
> [@njtt](#): > > Why would a sensor even be need for an on-ramp light? I can see the point of having sensors at an intersection, but I should have thought a simple timer would have been perfectly adequate for an on ramp. If there is no-one there, it will not matter if it is red or green anyway. Traffic management? ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [September 1, 2012, 1:54am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/22 "2012-09-01T01:54:13Z")
> [@Leaffan](#): > > Traffic management? What do you mean? The purpose of on-ramp stop light, surely, is to space out the cars as they enter the freeway. That _is_ traffic management, but so far as I can see a simple timer will do the job quite as well as a complex sensor-based system. Heck! It would do the job _better_ for **davidm** ’s car. (I am fairly sure the ones I am used to, in California, are simply on a timer. They work.) ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [September 1, 2012, 2:05am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/23 "2012-09-01T02:05:20Z")
> [@njtt](#): > > What do you mean? The purpose of on-ramp stop light, surely, is to space out the cars as they enter the freeway. That _is_ traffic management, but so far as I can see a simple timer will do the job quite as well as a complex sensor-based system. Heck! It would do the job _better_ for **davidm** ’s car. (I am fairly sure the ones I am used to, in California, are simply on a timer. They work.) So you think a timer toggling “red” “green” “red” “green” ad infinitum is better than a loop sensor that actually senses when traffic needs to merge? ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 1, 2012, 2:42am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/24 "2012-09-01T02:42:04Z")
> [@Leaffan](#): > > So you think a timer toggling “red” “green” “red” “green” ad infinitum is better than a loop sensor that actually senses when traffic needs to merge? What advantage does the sensor have? ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [September 1, 2012, 3:12am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/25 "2012-09-01T03:12:55Z")
A sensor on the highway detecting how much traffic is going on could be useful to determine if the on ramp signal needs to be active or solid green. A sensor on the on ramp to determine if the signal should turn green? That could probably be done by a timer. -D/a ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 1, 2012, 3:16am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/26 "2012-09-01T03:16:37Z")
I`ve seen these in some cities - they limit the number of cars entering the freeway over a given time - so the freeway itself does not clog when too many people try to merge into a not-empty lane. One city IIRC had two on-ramps, regular and hi-occupancy, so the sensors would be useful in that regard to give the high-occupancy car the green light first. The other advantage to sensors would be to ensure only one vehicle at a time went on. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [September 1, 2012, 3:44am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/27 "2012-09-01T03:44:37Z")
[Something to try using magnets.](http://www.wikihow.com/Trigger-Green-Traffic-Lights) > [@](#): > > There is a light I frequently have to cross with a proximity sensor that will not detect my motorcycle. [There is a product for that](https://www.google.com/#q=motorcycle+traffic+light+trigger&hl=en&safe=off&prmd=imvns&source=univ&tbm=shop&tbo=u&sa=X&ei=UYNBUMy_N4ObjAKtjYGgDw&sqi=2&ved=0CCwQsxg&fp=1&biw=1360&bih=599&bav=on.2,or.r_gc.r_pw.r_qf.&cad=b)or use the method suggested above. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [September 1, 2012, 5:21am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/28 "2012-09-01T05:21:10Z")
> [@Leaffan](#): > > So you think a timer toggling “red” “green” “red” “green” ad infinitum is better than a loop sensor that actually senses when traffic needs to merge? It can be more elaborate than that. Where on-ramps are metered, don’t they have traffic sensors _on the highway lanes approaching that ramp_ to detect the flow of traffic that is already on the highway, and use that to control the pace of the on-ramp light? The cite given in the OP tells of many different technologies, and many different metering strategies, that have been tried. ETA: Aha. I see that **Digital is the new Analog** has already pointed that out. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 1, 2012, 9:51am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/29 "2012-09-01T09:51:53Z")
> [@Telemark](#): > > Since it’s possible to trigger many lights in a bicycle if you stop in the correct place I don’t think there’s anything special about your car. I also suspect that you’re just not stopping in the right place. The right place for a bicycle is to put the tire directly on the black line where they buried the sensor. This technique may not work well in a car, since you don’t have a good view as to exactly where your wheels are. Also the tires on a car are thicker, meaning the rim is further away from the sensor, so it may not work as well. Once upon a time, I could get almost all local traffic lights to change by doing this. Then a couple years ago I had to buy new wheels for my bike. With the new wheels, some of the lights would no longer change. So I had to run red lights (after stopping and waiting for a large break in traffic, of course). Don’t like doing it, but what else can I do? ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [September 1, 2012, 11:18am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/30 "2012-09-01T11:18:36Z")
> [@racer72](#): > > [Something to try using magnets.](http://www.wikihow.com/Trigger-Green-Traffic-Lights) > > [There is a product for that](https://www.google.com/#q=motorcycle+traffic+light+trigger&hl=en&safe=off&prmd=imvns&source=univ&tbm=shop&tbo=u&sa=X&ei=UYNBUMy_N4ObjAKtjYGgDw&sqi=2&ved=0CCwQsxg&fp=1&biw=1360&bih=599&bav=on.2,or.r_gc.r_pw.r_qf.&cad=b)or use the method suggested above. Interesting; I didn’t know about that product. But before I waste $20 on something, I’d like to know if it works. Any engineer out there who can comment on whether magnets on a bike or in a shoe will have any affect on a proximity sensor, or is it just hype? ---
**Author:** ![Bookkeeper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bookkeeper/32/281_2.png) [@Bookkeeper](https://boards.straightdope.com/u/Bookkeeper)\ **Post date:** [September 3, 2012, 1:28am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/31 "2012-09-03T01:28:42Z")
The sensor loop doesn’t appear to be equally sensitive all around, as our city marks the most sensitive section with [yellow dots](http://www.ottawa.ca/en/roads_trans/driving/traffic/traffic_signals/detection/index.html) to indicate where bikes should stop to trigger the light. You may be positioned in the wrong location for proper sensing, coupled with a high threshold to trip the sensor that doesn’t register for the smaller amount of magnetic metal in your car. ---
**Author:** ![Kiwi\_Fruit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiwi_fruit/32/12_2.png) [@Kiwi\_Fruit](https://boards.straightdope.com/u/Kiwi_Fruit)\ **Post date:** [September 3, 2012, 2:22am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/32 "2012-09-03T02:22:10Z")
I have read in a motorcycle forum that stopping and starting the engine can help with inductive sensors. The pulse from the engine starter can be enough to be picked up by the inductive coil. I used to find one intersection in particular needed me to ride over the right part of the loop to be detected, but we are talking about a vehicle that is an order of magnitude less massive than an Insight. Even if the Insight is mostly non-ferrous, it doesn’t mean there is no field change that can be detected. ---
**Author:** ![davidm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidm/32/225_2.png) [@davidm](https://boards.straightdope.com/u/davidm)\ **Post date:** [September 3, 2012, 4:10am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/33 "2012-09-03T04:10:06Z")
That’s an interesting point about stopping and starting the engine. Since my car is a hybrid the engine sometime shuts off completely when I’m stopped. I don’t see how that could make any difference but it’s another piece of data. But really I’m thinking I must not be stopping at exactly the right spot. Considering the high voltage wiring and the load of batteries there’s certainly enough conductive metal. ---
**Author:** ![Seanette](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/seanette/32/9139_2.png) [@Seanette](https://boards.straightdope.com/u/Seanette)\ **Post date:** [September 3, 2012, 11:12am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/34 "2012-09-03T11:12:15Z")
I had wondered about weight of the vehicle, but if a motorcycle can trigger the sensor, a car shouldn’t have trouble (and my DH thinks a hybrid is likely to weigh more than a similarly sized “standard” vehicle). ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [September 3, 2012, 3:37pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/35 "2012-09-03T15:37:45Z")
Do you ever get skipped over when standing in line, or bumped into by other pedestrians on the sidewalk? It could be that the problem is not the vehicle. Perhaps you are no longer physically with us! ---
**Author:** ![Son\_of\_a\_Rich](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/son_of_a_rich/32/5439_2.png) [@Son\_of\_a\_Rich](https://boards.straightdope.com/u/Son_of_a_Rich)\ **Post date:** [September 3, 2012, 3:51pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/36 "2012-09-03T15:51:40Z")
Some places (I have no cite) allow motorcycles to run reds if the lights don’t change after a reasonable period of time, and if it’s safe to do so. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [September 3, 2012, 4:47pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/37 "2012-09-03T16:47:25Z")
I’ve had similar problems in my 2007 Aveo (non-hybrid). ---
**Author:** ![davidm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidm/32/225_2.png) [@davidm](https://boards.straightdope.com/u/davidm)\ **Post date:** [September 3, 2012, 7:08pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/38 "2012-09-03T19:08:57Z")
The hatchback or the non-hatchback Aveo? [http://www.google.com/search?q=2007+Aveo&hl=en&prmd=imvns&source=lnms&tbm=isch&sa=X&ei=2\_9EUPjbFOrv0gH2s4DwCg&ved=0CAcQ\_AUoAQ](http://www.google.com/search?q=2007+Aveo&hl=en&prmd=imvns&source=lnms&tbm=isch&sa=X&ei=2_9EUPjbFOrv0gH2s4DwCg&ved=0CAcQ_AUoAQ) ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [September 3, 2012, 7:46pm UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/39 "2012-09-03T19:46:07Z")
> [@Muffin](#): > > Do you ever get skipped over when standing in line, or bumped into by other pedestrians on the sidewalk? It could be that the problem is not the vehicle. Perhaps you are no longer physically with us! What’s the name of that Cary Grant movie like this? ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [September 4, 2012, 12:08am UTC](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268/40 "2012-09-04T00:08:42Z")
> [@Seanette](#): > > I had wondered about weight of the vehicle, but if a motorcycle can trigger the sensor, a car shouldn’t have trouble (and my DH thinks a hybrid is likely to weigh more than a similarly sized “standard” vehicle). The current-generation Honda Insight weighs 2700 pounds, which is about 100 more than the slightly longer, slightly wider Civic sedan. [QUOTE=Leaffan] And the transmission, and the axles, and tie rods, and ball joints, and hood, and fenders, and frame, and … [/QUOTE] The hood, fenders and frame on an Insight are aluminum, not steel. [Previous page](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268.md?page=1) [Next page](https://boards.straightdope.com/t/traffic-signals-not-sensing-my-hybrid-is-this-possible/633268.md?page=3)