How do they catch speeders without radar guns?

How long have radar guns been around? I ask this because I wonder how police officers caught people speeding. With a radar gun, you get a pretty accurate reading of how fast a vehicle was going (I guess) so its pretty solid proof whether or not someone sped or not. But it seems a bit harder to prove they were speeding just by visually observing them “He looked like he was going 63 in a 55 mph zone”. How did they nail speeders before radar guns were invented?

“Pacing.” On highway 280 in the Bay area, they can’t use radar b/c of the PARC and b/c certain communities that border the highway don’t allow it. What they do instead is creep up behind you and measure your speed by pacing behind you for 1/4 mile or so. Then they pull you over and say you were driving “around” 75 or whatever. Yes, most of the time I can see them coming up behind me and just slow down. But many, many people don’t pay any attention.

There can also be lines marked off a known distance apart, then when a car appears to be obviously speeding, they can time the passage between the lines and calculate the speed. Aircraft observers can help with this too.

I can think of two ways right off the top of my head. They could pace them by matching speeds with the car and looking at their own speedometer (hence the requirement for certified accurate speedometers in police cars. I noticed when I bought my 1996 Impala SS, it had a certified speedometer. Checked it against my GPS at 100mph, and it was 1 mph off).

Or, they could measure the time it takes to cover a given distance. Say you have a couple of lines painted on the road about 500 feet apart. A policeman could use a stopwatch to see how long it took you to cover that distance and compute your speed from that. They often do this from aircraft, but the method would work fine from the ground too, provided you have a clear view of both reference points.

Pleanty of tickets are written without the use of radar. There is VASCAR (a visual distance/time calculation) and the “bear in the air” (distance/time using an aircraft).

I don’t know if these pre-date the use of radar, but certainly distance/time measurement of speed is not new.

The cops could tell if someone was flying past, just like anybody could, and their word held up in court better years back.

My uncle told me about the only time he got caught speeding. I can’t remember the details but they had two plastic tubes lying on the road or something. I can’t remember what this is called.

The Delaware State Police got their first radar units in 1952:

I would guess most of the speeders they catch don’t have radar guns.

There was a book a while back written by a New York State Trooper on how to avoid tickets. In it he described a device, part timer, part odometer, this might be what Xema called a VASCAR, but I don’t know for sure.

If he thought you were speeding, he would watch you pass a landmark, and start the timer. He would then drive past the landmark himself and start the odometer. At this point, he would just zoom on past the speeder, as if he was going somewhere important. Once out of sight, he picks another landmark and stops the odometer when he passes, this sets the distance. Park on the side of the road and stop the timer when the speeder passes landmark #2, you now have a time and distance, check the speed, and pull 'em over.

In Austria the Cops are allowed to guess how fast you are and then fine you dependingly. Well, at least that’s what’s being told in Germany, maybe it’s just an UL, but I have heard this now and then from different trustable sources…

In the UK and Ireland, they have a belt and braces approach with un-manned (personed) speed cameras.

They have painted a number of lines on the road just past the camera and the camera takes two photos. The speed from the radar is printed on both photos but even in the fraction of a second between the photos, you can see how far the car has traveled. (This isn’t from experience, I used to work for a car hire firm)

The gridlines on the road also help you spot the camera ahead and slow down.

Slight hijack, but still a GQ: Why don’t the communities allow it, and what authority do they have over, say, state police using them? (Just curious.)

Huh, my first post appears to have been lost. Anyway, my question was, how can police departments justify the use of aircraft for speed enforcement? Do they just do it because they have a helicopter lying around anyway for high-speed chases and the like? Or have they convinced the local gubment that it’s necessary to keep speeding under control?

Is there something special about aircraft that needs to be justified above and beyond whatever justifications they have to use vehicles?

Well, yeah, there are. Aircraft are extremely expensive to own and operate, compared with patrol cars. As well, these cars are used all the time by the police for all sorts of reasons. Airplanes and helicopters, on the other hand, have limited use within the police departments. The issue is the cost; like every government entity, they’re held responsible for their budget by the taxpayers.

Here is an interesting article I read yesterday in the Pittsburgh Post Gazette. It seems that only the PA state police are allowed to use radar in PA; the local police have to use VASCAR.

Based on a book entitled “How to Avoid Speeding Tickets” written by a former NY State Trooper, the answer is:
They do not do it very often. Due to cost factors, this is done just often enough to keep the claim “Speed enforced by aircraft” credible.
The above is my recollection of the author’s comment on this.
My personal guess is that they don’t even have dedicated units for this, and probably use the same police choppers they’d otherwise be using in emergency situations for this application. And they probably don’t do it very often.

Airplanes are going to cost at least $70 an hour. The documentry I watched on the subject made it seem more like a gimmick than anything else. Something to show speeders how “high tech” speed detection has become.

I’ve been trying to find a cite for this, but I’m afraid I just have what my friends told me. (And the fact that I’ve been pulled over twice in 8 years, driving back and forth every day, and neither time was radar involved, nor has any radar detector ever gone beserk in whatever car I happened to be in).

What I’ve been told is that the cities along 280 on the Peninsula have to donate a radar gun to the police. Woodside has one, but most of the other cities (pretty ritzy places) do not. I don’t think they have any authority over the state police, it’s probably more like the state police doesn’t have to use them. The road is pretty curvy, so they have places to hide, and they have plenty of business out there. I can’t tell you how many times I see one coming, slow down, and then three cars blow right by me and one gets pulled over.

Plus, there are large stretches of road that border PARC (Palo Alto Research Center) and different science buildings at Stanford that are doing scientific things that probably don’t allow radar use. There’s a particle accelerator and a satellite dish right next to the road also.*

*[sub]before Johnny science guy storms in here, no, I have no idea whether or not radar would interfere with these things, it’s just what I’ve been told.[/sub]