Dim traffic sensors dull how 'smart' freeways are

[ZLoth]

From SF Gate:

Dim traffic sensors dull how 'smart' freeways are

California's highways aren't as smart as they used to be.

Buried under thousands of miles of pavement are 27,000 traffic sensors that are supposed to help troubleshoot both daily commutes and long-term maintenance needs on some of the nation's most heavily used and congested roadways. And about 9,000 of them do not work.

The sensors are a key part of the "intelligent transportation" system designed, for example, to detect the congestion that quickly builds before crews can get out and clear an accident.

FULL ARTICLE HERE

[Alps]

May as well take this opportunity to use new detection technologies like infrared, radar, magnetic... Loops are the old way and have many drawbacks, as this makes clear - replacement effort being one.

[hotdogPi]

What exactly do these traffic sensors do?

[Zeffy]

What exactly do these traffic sensors do?

My guess from reading the article is that they detect buildups when an accident happens and send it to various services. (such as Google Maps' traffic conditions)

[cpzilliacus]

May as well take this opportunity to use new detection technologies like infrared, radar, magnetic... Loops are the old way and have many drawbacks, as this makes clear - replacement effort being one.

Bluetooth receptors are being used for these sorts of things in some places.

Loops are indeed the old way, and have to be replaced every so often, especially in places where salt is used for winter maintenance.  Though I would think that there's not much salt used in the immediate L.A. and San Francisco Bay areas.  Though they do get snow in the mountains north of the L.A. Basin.

[Indyroads]

traffic sensor cameras and microwave/infrared technology is the way to go here. Especially due to the difficulty in replace loop sensors.

[roadfro]

Nevada DOT still installs/maintains loops in many highways. Most of these are used as count stations.

However, along the urban freeway networks, NDOT has been moving toward microwave detectors. The FAST office (run by RTC of Southern Nevada with NDOT support) began using microwave detectors spaced roughly every 1/3-mile on I-15 & US 95 in the Las Vegas area several years ago, and they've started rollout onto Summerlin Pkwy and the 215. These detectors provide count and speed data, which fuels information for the travel time displays. The recent design-build project on I-80 in Reno also installed these same style detectors, and I believe they are looking into adding them along US 395/I-580.

[Occidental Tourist]

Loops are indeed the old way, and have to be replaced every so often, especially in places where salt is used for winter maintenance.  Though I would think that there's not much salt used in the immediate L.A. and San Francisco Bay areas.  Though they do get snow in the mountains north of the L.A. Basin.

LA traffic has not spread to the mountain passes that get snow.  Not yet, anyway.

[cpzilliacus]

Loops are indeed the old way, and have to be replaced every so often, especially in places where salt is used for winter maintenance.  Though I would think that there's not much salt used in the immediate L.A. and San Francisco Bay areas.  Though they do get snow in the mountains north of the L.A. Basin.

LA traffic has not spread to the mountain passes that get snow.  Not yet, anyway.

I-5?  Ca. 14?

[tradephoric]

April 2013,
FIELD EVALUATION OF SMART SENSOR VEHICLE DETECTORS AT INTERSECTIONS–VOLUME 2: PERFORMANCE UNDER ADVERSE WEATHER CONDITIONS

16. Abstract
Two microwave-based systems for vehicle detection (by Wavetronix and MS SEDCO) were evaluated at stop bar and advance zones of a signalized intersection under three adverse weather conditions: (1) wind, (2) snow-covered roadway, and (3) rain. Weather effects were very different for the two systems both in terms of the type of condition that could affect performance and in the magnitude of those effects. For Wavetronix, wind had significant effects on the advance zone by increasing false calls to over 50%, but it did not affect the stop bar zones. On the other hand, false calls in snow significantly increased to more than 40% in the stop bar zones and to about 30% in the advance zone. Snow also increased missed and stuck-on calls but in lower proportion than the false calls. Rain also affected the detection at stop bar zones, but all error types were below 8%, and it did not affect the advance zone. For Intersector, weather effects were less pronounced both at the stop bar and advance zones. Snow increased false calls to a range of about 4% to 8% compared to 1.65% to about 4% in normal weather. In addition, rain increased stuck-on calls to a range of 2.7% to 6.35% at the stop bar zones and increased missed calls at advance zones to 3.44%. Wind had no significant effects at stop bar or advance zones. In particular for the rain data, the intensity of the precipitation seemed to be related to the degree of performance degradation. In datasets with higher precipitation per unit of time, higher false calls were observed at Wavetronix stop bar zones, and a higher frequency of missed calls was observed at the Intersector advance zone. Findings from this evaluation can provide valuable information to users and manufacturers of these products regarding expected performance under adverse weather conditions at locations with similar mountings and settings, as well as insight about potential solutions to preventing negative effects in such scenarios.

One microwave detection system had up to a 50% false-call rate under certain weather conditions.  That's been the problem with a lot of these new detection technologies... under certain weather conditions the accuracy fails.  A lot of the selling points of these supposedly advanced technologies (I.E easy to install, less invasive) are moot points if the accuracy isn't there. 

Because they know all they sold ya was a guaranteed piece of shit. That's all it is, isn't it? Hey, if you want me to take a dump in a box and mark it guaranteed, I will. I got spare time. But for now, for your customer's sake, for your daughter's sake, ya might wanna think about buying a quality product from me.

[Occidental Tourist]

LA traffic has not spread to the mountain passes that get snow.  Not yet, anyway.

I-5?  Ca. 14?

Proving your point, Caltrans has installed loop sensors on those parts of the 5 and the 14 that get snow.  Proving my point, those areas (respectively Castaic to Fort Tejon and Acton to Palmdale) don't have any significant daily traffic.

Mooting both of our points is the fact that Caltrans runs plows and rarely uses salt.