I have a question about those radar units on the side of the road stating your speed. Are they there so the cops know how many are speeding in that section so they can set up a future speed trap or so that if 80% of the people are going over the current limit that they might increase the limit in the future? So is it better to go by slow so they won't set up a trap or to speed thereby raising the average hoping for a higher limit? I have a feeling it's the first because it seems I always see a trap weeks later.

 

I always thought they were photo radar. They take a pic of your plate if your speeding & mail you a ticket.

 

That can't be it because I've been blasting through them for years and never got a ticket from it. I'm tempted to throw a brick at the bastard and take it out.

 

i always thought they were meant to make u slow down out of fear u're gonna get nailed

there have been times out in the Hamptons where there's a cop car sitting on the side of the road and a DUMMY in the driver's seat, just so people will b scared into slowing down hehehehe

 

I think they're just there as an FYI to try and deter speeders. I've never heard of one of those contraptions taking pictures, since I've been speeding by them and haven't gotten any tickets mailed to me.

 

Those signs are there to check the accuracy of your speedometer. Now when my speedometer says 99, I know I'm only going 98. Thank you Phoenix PD.

 

They tried that here and their car was stolen.

 

 

now that's what i'm talkin about

 

Unless those units have cameras, they can't be used for enforcement. If you'll notice, those devices are in plain view. The speed enforcement unmanned cameras that I've seen have always been hidden or positioned just like a patrol cop (i.e. around the curve, over the hills, in the trees).

I would rather believe those are fyi remote units. They usually have a pretty short range and they do show speeds in all lanes and all directions which means they are probably not gathering and using meaningful data.

 

They're there for you information. It normally results from people in the area complaining about speeding, and the local fuzz put up a unit to try to educate those people driving there..

 

2- things I like about the mobile speed pokers:

1. see if I can make it read triple digits, eventhough it can only display 2 on the board.

2. and testing out the range and accuracy of my radar detector.


fawk'um!!

 

it would say "HI"...don't ask me how i know this

 

Fortunately,there is not a single photo radar in wa state..and i always obey the speed limits (maybe over 3~4 miles).. or follow the other cars' speed

 

I didnt think they could mail you a ticket because it is a moving violation which goes onto your license. What if I lent my car to a friend and he was speeding? How could i get the ticket for that just because it was my car?

 

I used to work for a company in KY that made these things....

They are primarily to inform people of their speeds. As we all know.....80mph in these CLs feels like 45-50 in most other cars (at least the ones I've had)....the damn motor just doesn't work that hard at 75-80mph!

They are also normally used when the local PD doesn't have enough staff to cover all the "hot" areas. Therefore, a dummy is often used in conjunction.

 

They are good and bad(if you ask me) the good part about them is Like if you guys get like 18 or 19 inch rims and your speedometer is off you can run down there (if it's 35) and your actually run like 45 you can know how much it's off by.
the bad thing is. I've seen cops(they'd almost hide behind a building turn at night(so it's hard to see them) and just watch those "YOUR SPEED SIGNS" and as soon someone over they'd come hell bent for texas out of there after the speeder. (I know it's sneaky). I once thought about taking my bike down there and petalling real fast and see if i can break the speed limit see if the jerk offs would pull me over. (but knowing that town they would).

 

Everybody has been wrong. The 'your speed' sign/radars that are put up on various streets are part of mandated traffic surveys used to create new or justify old speed limits.

Municipalities/cities (etc) are required to periodically survey the average speed limit of drivers on certain roads. I think the requirement is every 4 years per segment of road (I could be wrong on the interval).

Say a given street has a speed limit of 40mph. The city needs to survey what drivers are actually doing to justify this speed limit. If everybody goes 40 or lower, then the speed limit is sound (or may need to be lowered). If the average driver is going 50, then the speed limit may need to be raised.

The going recommendation is to SPEED through those radars. Of course this is a catch-22 - if a cop is near by, you are toast.

If enough people speed and the average speed is raised then the posted limit is WRONG (sort of). If you go to fight a speeding ticket on a city road, you should ask the city for the most recent survey. If the posted speed limit is 40 and the average speed driven is 50, and you were caught at 50, you may beat the ticket for a improper posted limit.

Of couse the big catch is that most people see that radar and slow down - and this drives the average down and therefore the posted limit won't change. Do all speeders a favor and try to UP THE AVERAGE SPEED that the thing measures!

(This information comes from a book I read long ago about how to beat a speeding ticket - I've never needed to go to court to challenge a ticket myself, so I cannot verify the validity of the above stated defense. I do speed up when I see those radars though)

 

Around here, the signs are usually put up in areas where people complain about speeders (generally in neighborhoods) or where the traffic normally runs fast (eg. I-64 near Hurstbourne). A neighbor of mine complained about traffic, and a couple of days later, one of those signs was standing guard. Then, a few days later, the sign was replaced by a patrol car, and the ticket-writing began.

This is their normal use in this area. They are put up to warn people that they are going too fast. Then, they are replaced by patrol cars that follow up on the warnings. They are not used for traffic surveys to change the speed limits. Speed limits are based on common criteria across the state (type of road, area congestion, number of lanes, etc.) and not on how fast the average driver can fly by a sign.

 

I am not an attorney, nor do I understand all language of the law. Laws also differ from state to state. However, traffic surveys are performed to maintain and justify speed limits in certain locales. Traffic surveys are conducted, in part, by those radar thingys to obtain statistics on driving speeds on certain roads. It seems that the understanding of traffic surveys are key in defense of certain tickets that one would argue were obtained by a 'speed trap'.

As you state, they may also be used as a 'reminder' and warning to speeders as well.

I was wrong on the year interval. It seems, in CA at least, that the survey should be done every five years, however there seems to be loopholes as well.

Just do a google search on 'traffic survey radar', you'll get a lot of hits. For instance: http://helpigotaticket.com/cases/goulet.html

 

O.K. i'll start blowing through those when i see em

 

FYI - I found the CalTrans Traffic Manual that states how you are not entirely right (at least in CA). Here is a selection:

Because there is a basic speed law that is set up to maintain limits that are reasonable and prudent, the speed limit for many zones is based off the 85th percentile of how people drive (maxing out at 55/65/75mph depending on zone), as long as it's safe (ie: accident survey agrees).

Of couse, the big bummer is that most people see the big radar detector and posted speed limit and then hit their brakes. The average speed drops and the city is supported in the 'posted' speed limit. Nice way to set up a biased survey.

And yes, those radar detector thingy's are one way that the traffic engineers survey the conditions. Sometimes they use tube thingys that they string across the road. Assuming the ideas above are upheld, it would make sense to do what you can to increase the average (and therefore the 85th percentile) speed measured during a survey. If everyone travelled faster, and there are no accidents, the posted speed limit can be deemed inappropriate.

I don't know (and don't care) if similar legislation exists in KY.

 

Bwhahahahaha gotta love B-more.

 

I think we're all getting a bit confused about this whole thing.

Most of what Slim is saying is correct except it's out of context. Yes, traffic studies are required but the fact is they aren't being done as frequently as you might think. For the most part, nobody seems to care. So you might beat a ticket or two if you dig and dig...etc.

But I'm almost sure (and let's ask our manufacturer friend) that the engineering studies are NOT being performed by a hunk of junk which consists of a K-band radar poorly mounted on a trailer. It just doesn't make sense and here's ten reasons why:

1.If you look closely at those trailers, you don't see any type of data collection devices attached. Traffic surveys need number of data points, real data points, time of day, etc. How you get that from a radar on a trailer I don't know.

2.Usually on those trailers you see 'THE SPEED LIMIT IS 35' and the name of your local PD. Why would a traffic survey have this information plastered all over the trailer? If I'm an engineer and I'm suppose to rely on data collected from this biased medium? Unless you subscribe to the "let's lower the speed limit" conspiracy theory....why not just put a flashing blue light on top while you're at it.

3.If you have seen the lines across the road that are really used to collect information, you'll see that a) They don't cross all lanes of traffic going in all directions and b) They are layed to distinguish different speeds in different lanes (sometimes) and c) They can actually count the number of cars that pass by (not trucks) because there are multiple lines layed at a know distance. How you accomplish this with K-band radar that will clock cars in ALL directions, subject to all kinds of errors, and even clock birds, I don't know.

4.When you see this device traveling across town, it's usually being towed by your local PD. I guess they now take orders from the road crews. I see that damn trailer on this side of town this week, in my neighborhood next week, it disappears for 4 weeks, then it's outside my workplace (i.e. Sprint must have rented it for a week, it was on Sprint property). Traffic survey my ass.

5.Not trying to say they don't use similar devices for this, all I'm saying the original poster was alluding to such signs that we all seem to know is used for traffic fyi and not road surveys.

6.Honestly I think a police department would be remiss if they used the speed reading from this device to catch you speeding. Can it aid them in their work? Yes, I see it says 65 in a 35 so I pace you or clock you myself. I doubt the police have the calibration paperwork for these signs to enforce a ticket in court. With their car-mounted or handheld gun, they get a thick big book and much training on how to go to court with one of these. As for the 'your speed' signs, how to train someone to know which car is responsible for that visual? Especially when you're behind everything..... Not saying the police don't do this or that they do show up tomorrow in place of the sign, just that I can't believe the police would place a patrol car behind one of those and look at the sign's visuals for reliability.

7.What would be the purpose of visually displaying the car's speed during the collection of data? Can you name any other device used to collect data that provides such a visual indication?

8.Those radars mounted on a trailer, yes the same ones that we've been talking about all throughout this thread, well it actually measures your speed constantly. If you are the only one on the road, you can watch your speed on that big display go up and down and up and back down for the 15 or 30 seconds that you are in front of the radar. What the hell kind of data is that? I'm suppose to analyze this and try to make ascertain if people are speeding? That kind of constant data stream with multiple, multiple data points as opposed to the single point that you get when a car crosses over a line makes the radar output useless.

9.Look at where those signs are located. Do you ever see them in places where they look like they are conducting engineering surveys? (as if we know what such a place looked like) But anyway, no they are a) when you're going into the airport and b) in and around school zones and c) in neighborhoods where people speed and d) on stretches of road where you can clearly see the sign before you are caught on radar if you were looking (IOW they don't be trying to hide them).

10.Who is responsible for traffic surveys? The State? Then why do city PDs own/lease these trailers?

 

Oh, I thought those things were games to entertain us on long trips so we dont fall asleep. Object of the game... achieve the highest score.

 

Good points kensteele. Maybe I did get sidetracked, and maybe I've seen the device used differently then others have.

I think that the device may be applied differently in different places.

I've never seen one towed by a police car or display the local PD badge. In Los Angeles they were placed by CalTrans.

I've seen them placed on all sorts of roads, not just near schools, etc.

There is a large 'black box' attached to the ones I've seen. This could be the 'brains' that logs data, but who knows?

 

Ah. See, we're talkin' about different things. The ones that I've seen here, like Ken pointed out, are all owned by the police departments and don't seem to have black boxes. I'm sorry that I assumed all the speed boxes are the same. You seem to have some out there in CA that aren't. Damn Left Coast.

 

those things just get in the way out here , they put them out on half on the road,,, stubid things , allmost hit one too

 

I use 'em to check my speedo accuracy. I also use them to see how far the local federales' radar reaches my V1!

 

Kensteele you are 100% right on. Those "Your Speed Is" devices are nothing more than community policing/public safety feelgood boxes. They are *not* speed limit survey devices. Slimey is right in the fact that cities and towns can petition to change a speed limit and they do so by conducting a traffic survey, and also that speed surveys are done by NHTSA from time to time for traffic studies. But NHTSA (National Highway & Traffic Safety Administration) has very strict rules on how these are done. Rule #1 is you *cannot* use unmanned devices for survey purposes. There is a method that must be followed to count the number of cars going at certain speeds. And yes, the 85th percentile is the rule of thumb for setting limits. This is why it can be dangerous for a town to try and petition a change. Let's say a limit is 35 and the town wants it at 30. If a survey is done and the 85th percentile of speed is 40, the state DOT or NHTSA will say, okay we'll change it but it's going to be 40 now instead of 30. Local roads have more leeway, but state roads and interstates are all set by federal regulations.

And yes, the rubber tubes across the road are for counting numbers of cars only--nothing to do with speed at all.

And another thing--most of those boxes don't have radar units that are calibrated (or checked) according to NHTSA standards. Usually they just wheel it out to where they want it and plug it in. If you ever got a ticket as a result of the reading displayed on one of those things, you'd have a good argument to get out of it.