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View Full Version : anyone seen the radar guns on the lightpoles on I-95



odortiz
11-10-2005, 10:02 PM
on a few lightpoles between northbound and hov on I-95, there are radar guns aimed at traffic and fire off k-band radar for a few seconds every 10 seconds or so. they have a little solar cell above them. they are placed about 20 feet from the ground.
i've seen them in my drive from woodbridge to alexandria.
anybody know what they are for?
anybody else seen them?

OwnedbyDuncan
11-10-2005, 10:08 PM
It is a classified DOD/DHS project. Details will appear shortly in the MSM because of a leak. It deals with a possible WMD attack by terrorists and pizza delivery.

Dave Apker

AlfaEric
11-10-2005, 10:29 PM
on a few lightpoles between northbound and hov on I-95, there are radar guns aimed at traffic and fire off k-band radar for a few seconds every 10 seconds or so. they have a little solar cell above them. they are placed about 20 feet from the ground.
i've seen them in my drive from woodbridge to alexandria.
anybody know what they are for?
anybody else seen them?
I'm guessing they collect traffic speed data.
http://www.chart.state.md.us/TravInfo/speedData.asp

---Eric

1996 328ti
11-10-2005, 10:33 PM
Kinda tells you that the speed limit should be 65. :)

AlfaEric
11-10-2005, 10:39 PM
Kinda tells you that the speed limit should be 65. :)
At times I think they should just remove the limits on some roads. Seeing a speed limit sign while going 5 mph on the highway in traffic just pisses me off. :mad:

---Eric

Pinecone
11-11-2005, 07:38 AM
Kinda tells you that the speed limit should be 65. :)

Or higher. Notice they don't report an actual speed above 65? :)

ob325
11-11-2005, 02:03 PM
on a few lightpoles between northbound and hov on I-95, there are radar guns aimed at traffic and fire off k-band radar for a few seconds every 10 seconds or so.

They are on 395, too. I hate them. But it's not like I can write anyone and complain about that. :icon_frow I test my reaction time to see how quickly I can silence the buzz.

And what good do they do? Whenever you see the "average speed" reported on TWC or the news, it is never above 54mph, yet I've been on there many times when everyone is going 65+ easy.

odortiz
11-12-2005, 08:56 AM
between woodbridge and alexandria at about 8 pm, everyone northbound travels about 80-85

JCFLYS
04-28-2006, 09:58 PM
They call them Radar Drones in California. Its just another way to piss us off. It sets of your detector if you have one and must be part of their agressive driver imaging program.

mlytle
05-01-2006, 10:49 AM
They call them Radar Drones in California. Its just another way to piss us off. It sets of your detector if you have one and must be part of their agressive driver imaging program.

yep. connecticut has them every half mile or so on i95 from new york to new haven. render radar detectors effectively useless.

David Hicks
05-08-2006, 01:24 PM
I've been going slower to save gas recently. At 60-65, you better be in the right lane of these roads (I 95 and I 395 in VA).

Dirichlet
05-08-2006, 02:06 PM
I've been going slower to save gas recently. At 60-65, you better be in the right lane of these roads (I 95 and I 395 in VA).

odd... I find that my car is most efficient at about 80mph, where I get 29-30mpg...
I'd like to see an actual efficiency/speed curve of the average modern vehicle - I'd be willing to bet that the most efficient speed isn't the 50-60mph they'd like us to believe. If the typical 70's through mid-80's car (shaped, effectively, like a brick) was most efficient around 50mph, I'd be willing to bet a hefty sum that the average car today operates best around 70mph... again, I have no proof of this, save what I have observed in my car, but it would be interesting to see.
(it may also be the anarchist in me getting pissed when I see the signs saying "slower speeds save gas" - I don't like the man trying to slow me down by capitalizing on current oil price economics... :p )

David Hicks
05-08-2006, 03:01 PM
It doesn't matter how aerodynamic your car is - drag increases with the square of velocity.

I wish I had time to do a little more research and really respond, but I'm swamped. You might be right that 55 mph is no longer the ideal speed, but I'd be very surprised if it were as high as 80. I've found the key to good mpg is to drive downhill as much as possible.

Dirichlet
05-08-2006, 03:41 PM
drag increases with the square of velocity.


True


It doesn't matter how aerodynamic your car is

False
The total force of air friction (drag) is given by
f = .5*C*A*V^2
where A is the area and C is the numerical drag coefficient. The point I was making is that today's vehicles have a greatly reduced coefficient of drag (C*A). Thus, for the same force (load on the motor), you can achieve a higher velocity...
Let's take a car with Cd = 0.6 v.s. a Cd= 0.5... the car with the lower Cd would be as efficient (given the same engine) at 66mph as the higher Cd would be at 60.

Pinecone
05-08-2006, 07:22 PM
And there are differences in the efficiency curves for the engine versus RPM and with gearing, the higher speed may get you into a more efficient area of the fuel use curve.

SharkD
05-08-2006, 10:35 PM
The 6 gets 25mpg at ~3250rpm in 5th gear... around 79mph. Any faster or slower and it drops to around 22mpg. (Or if I open a window, vent the sunroof or turn on the A/C.)

The 3 gets 8mpg at 5300rpm... :D

It used to be that there were days when I could leisurely cruise the E30 at 35+mpg.

David Hicks
05-09-2006, 06:56 AM
It doesn't matter how aerodynamic your car is - drag increases with the square of velocity.
I stand by this statement when taken as a whole. Drag force increases directly with Cd and with the square of velocity, therefore velocity has a bigger effect on the total drag force than Cd.

I agree that a more modern, low-drag shape can go faster for X amount of drag force than a more brick-like shape of an older car. However, since velocity plays a bigger role than Cd, in a general sense, slower is more efficient from a gallons/hr standpoint.

That argument obviously leaves out the gearing and the efficiency of the engine at various RPMs. I wouldn't be surprised if automakers have changed the gearing to optimize fuel economy as world speed limits (and real world speeds) have gone up. I'd be interested to find out where an M52 or M54 produces the most hp/gallon. If you had that, you could do some minimax calculations to determine the greatest efficiency in terms of gallons/mile/hour, which would take into account speed and overall fuel consumption.

ob325
05-09-2006, 08:05 AM
I've found the key to good mpg is to drive downhill as much as possible.

You have that right! I love to see the econometer go to the 50mpg+ range. Especially when I spent $43 for gas this morning.

Dirichlet
05-09-2006, 08:50 AM
... when I spent $43 for gas this morning.

what was that, a half tank...