Speed Trap

[Nellie]

What is a speed trap, and what is wrong with them? Why aren't they supposed to be used?

[redhead]

What is a speed trap,
Here is the CVC on them (http://www.dmv.ca.gov/pubs/vctop/d17/vc40802.htm) and what is wrong with them?
Why aren't they supposed to be used?I think this is one in the same quesiton, that maybe an officer can help with the ins and out of why the law is around.

[Nellie]

So, based off what I gleamed from that (and what I could make of the indexing scheme of the text), a speed trap is:

1. Using markers along the highway to determine speed.

OR

2. Using an electronic devide to determine speed if the speed limit has not been justified "by an engineering and traffic survey" within:

a. Seven years
OR
b. Ten years, if after seven years an engineer determines that sufficient changes haven't been made to the roadway (or adjoining areas).

Exception:

Local street, road, or school zones.

Does this mean that you can use what is normally referred to as a speed trap in a local street, road, or school zone?

If I am way off base, please let me know.

[redhead]

this was posted in my Aircraft post, and this really helped me understand it"

A speed trap, as defined under California law, is ANY method used to determine a violator's speed in which a formula using time, distance and speed is employed. If you remove one of those elements; time, distance, or speed, it ceases to be a speed trap by definition.

[dw]

A system called VASCAR is common in other states. It records time & distance and does the math as necessary to compute the speed of a vehicle. My belief is that this is what the definition of a speed trap is targeted towards.

http://www.vascarplus.com/Pages/How_it_works.htm

While there is nothing inherently wrong with the idea, it is politically incorrect. In my book, it's along the lines of the state trooper shooting RADAR from behind the billboard. While it works, it's playing dirty. I used to read ba.motorcycles, a population that certainly has an above-average rate of encounters with uniformed members of this Department. Every once in a while someone would pop up and complain about getting a ticket from a Chippie. The general response was that if you got a ticket from us, you most likely deserved it. It is recognized among the motoring public that we [generally] don't play "dirty."

My point is, if chasing sped without using a "speed trap" helps us to gain the respect of those we serve, than I'm all for it. It's not like it's hard to write legitimate speed cites all day using good old-fashioned pacing. Pacing is an art. Flipping a switch (or for that matter, turning on a RADAR) is something anyone can do.

[Mac]

By "electronic device", they're primarily referring to radar enforcement. If you use radar on a road that doesn't have a valid traffic engineering survey on file (with the exceptions you listed), it's considered a speed trap and the citation will be dismissed. Local roads (by definition) and school zones don't require traffic engineering surveys to use radar - so you can use radar for enforcement in those areas, but you still can't use time/distance/speed measurement methods (i.e. stopwatches over a marked stretch of road) - those can't legally be used anywhere in the state of California.

As far as I know, the only objection to speed traps is that they're considered "dirty pool", as dw said. I also agree with him that pacing is more entertaining than shooting radar. :smile: You could teach a monkey to use radar in about 10 minutes - pacing is more of an art.

[CHPwannaBE]

So, how does pacing work in the CHP?

[Darth Choke]

So, how does pacing work in the CHP?

just get behind the subject vehicle and match speed with it. simple.

[dw]

...and make sure they don't see you.... and you don't hit any other cars... or drive off the road... or spill your coffee...

As Darth said, fundamentally, it is as simple as matching speeds. Preferably, though, you're not right behind the violator, as that tends to contaminate your evidence. (Speeds often slow rapidly before you've established enough evidence for a conviction)

I like odometer pacing. In fact, I think Your Mentor was the first to explain the concept to me. Basically, you can pace someone several tenths of a mile behind and determine whether you're closing on them, increasing the distance, or remaining steady. Most will never know you're back there.

[dw]

This is a speed trap!

http://www.snopes.com/photos/automobiles/radar.asp

[Your Mentor]

Ah the sweet odometer pace. It truly is an artform. And yes, it can be done from as far back as 7 tenths of mile back. Beyond that it's hard to tell when a target passes a checkpoint. This still meets the definition of a pace because NO formula is employed. You simply maintain your speed and determine a change in relative distance between your car and the target. Very stealthy.

As for the reason behind the speedtrap evidence law: it dates back to Roseburg in the California Surpreme Court. Another very liberal law which has never been challenged. Again, it was believed, at that time, that speeding and speed enforcement constituted a game of sorts. And the rules needed to make it fair for the violator. Vascar was actually used in California before this law went into effect.

[x MAIT]

I was a VASCAR operator and instructor when in I was a MP in the Army back in 19__, oh, I forget. The idea behind VASCAR was simple. It measured the time it took a vehicle to travel a certain distance and calculated the speed. The problem with the system was that the operator had to input the time by flipping a toggle switch. This could easily be manipulated by flipping the switch too fast, which would calculate a higher, and incorrect, speed. You can see how this could easily be misused.

I can still hear the judge who handled traffic cases on the post say "VASCAR doesn't lie, guilty." Well......

[retchp]

More about odometer pacing...This is a little complicated but works. When you run an OD check the only thing you know is how fast you are going (70 for example) and how many tenths behind a vehicle you are thru checkpoints (overcrossings, curves etc). Thus you can say, I was 3 tenths behind the subject on my first check at 70 and 5 tenths behind on my second check at 70 so the subject was going faster than my vehicle or faster than 70.

Here is the trick...If you ALSO document the distance between the checks by writing it on your note pad or remembering it...first overcrossing reading 132.7 miles...second overcrossing reading 133.2 miles...DIFFERENCE .5 miles.

NOW you know that during this pace at 70 mph you were pulled two tenths of a mile over a distance of five tenths of a mile.

Simple arithmetic of five divided into two (Tenths) tells you that the subject vehicle pulled you 40 PERCENT of the distance of five tenths...thus is going 40 PERCENT FASTER than your vehicle. You are going 70 mph...40 percent of 70 is 28...70 (your speed) plus 28 (his speed) wquals 98 mph as his actual speed.

Now you can close and be ready to drop speed to about 95 rapidly and bumper pace him although you really don't need to do that since you already paced him by OD.

This works at all speeds and distances and a calculator is a big help. Using it you can do OD paces at the speed limit and just do the math to get the violators speed. I never testified to this in court, since it really is mental VASCAR...but it works. I ususally just said I ran OD paces blah blah blah which I in fact did. I just wanted to know the actual speed in case I blew the bumper pace. Any comment MENTOR? X-MAIT?

[Your Mentor]

retchp,
You're right, if you testify to that mental math you've met the definition of a speed trap. There are more sections, as you'll remember, that deal with any officer who testifies as such. As you pointed out though, you did pace the target vehicle and you were using your mental math only to double check your pace. But testifying to that back-up math would most likely meet the formula. I knew officers in the 4XXX badge number range who explained your demonstrated math to me and I tried it once or twice but eventually gave up because my brain is math-tarded. You, on the other hand, are a math whiz, as clearly demonstrated in your post. My head was spinning from your "Simple arithmetic." Two thoughts came to mind while reading that paragraph; "Wow" and "Cool." Anyway, I always just clicked off the check points, two or three, or four if I was bored, swooped in for the bumper pace, and made the stop. With radar, I almost NEVER use any paces now. I don't know how I feel about that. I do know that if I get an opposing speed well ahead of me, I lock it and turn on my overheads before we pass each other. I hate chasing people anymore and want their attention immediately. Before we had radar, in the desert four lanes, the odometer pace was the only way to work speed. The time you spent doing the odometer pace was more than compensated by the astonishment on the violator's face. Remember that question, "Where the hell did you come from?" :biggrin:

[x MAIT]

Kelly, you confused me with retchp. He gave the math quiz. I just mentioned that I used VASCAR when I was in the army. :biggrin:

Having worked my entire career in LA, traffic didn't allow for extended paces. I would just slide into the blind spot and get as long a pace as I could, or for ones ahead of me just set my speed and see if they were pulling away or not. One tenth mile was the norm. I didn't break out my calculator until I got into MAIT. Now, if you want some fun stories about using the 6-point equation to calculate speed from crush, I'm your man. :biggrin:

[Tom]

The brand spankin' new handheld radar units have a time function. If you program the distance between two known points and as the vehicle passes the points you pull the trigger and it calculates the speed.

Tom

[Your Mentor]

You're right xMait. Sorry. But Bob's math quiz was pretty cool.

Tom, I just received the new radar HPM last week. Haven't had a chance to look at it but I wonder if it addresses using that function on the new unit. Since any radar is considered a speed trap unless the road is surveyed, I wonder how that feature will be attacked once it gets out that our equipment has it.

[x MAIT]

The very best part of the bumper pace is when you are in their blind spot in the very next lane, and you can see that the driver is continually checking his mirrors to make sure that he doesn't get caught. Seeing their reaction when you slide in behind them and light them up was always a treat. Sign in the red box. Press hard, four copies.

[Tom]

I LOVED it when digital speedometers were the "in" thing. Like the Caprices. I would cruise the blind spot see the speed and voila!

Tom

[Mac]

I LOVED it when digital speedometers were the "in" thing. Like the Caprices. I would cruise the blind spot see the speed and voila!
LOL....yep, makes it pretty hard for them to argue when you point out that you were sitting in the blind spot reading their speedometer at 86 mph! :badgrin:

[SB 405]

I knew you guys always hung out in the blind spots. Now I know where the saying "I never saw you" originated.

[retchp]

In olden times we just used one inch per mph. Forty inches of crush meant at least a speed at IMPACT of forty mph for example. I would be interested in the relative accuracy of that rough rule of thumb if XMait can elaborate.

[x MAIT]

retchp,

There are many "rules of thumb" that have shown to be accurate, or pretty close. It's fine to use them as an aid. You would have major problems attempting to use it in court. It's like using .7 as a friction value or 1.5s perception and reaction time; they are useful as a rule of thumb, and when testifying about a citation. However, none of these things will stand up in a MAIT level trial. You will be requested to support your analysis with actual studies, testing, etc. The big deal with crush is that different cars crush differently, and different parts of cars also crush differently. You must admit that 40 inches of crush to the front of a car, which is stronger, heavier, and has a large engine behind the grille, would indicate more speed than 40 inches of crush to the rear, which is normally a large, empty space once you get past the bumper. Crush is also different when you are talking about running into a tree or solid wall, as opposed to two cars running into each other, where vehicle weight, size, speed, direction, and construction are factors.

[retchp]

Thanks for the response. I know that to be in MAIT you had to be a math whiz and understand a great deal about various studies and so on. When I came on we didn't have anything like MAIT of course, so we were reduced to learning from old timers who "knew a few things" or had actually studied physics or attended advanced programs like a traffic institute.
I once worked a bad crash involving tire failure at high speeds and got to work with a team of experts from the tire factory and their lawyers. Very interesting what you can interpret from the mold markings as an example (those little hairlike stubs found on the sides of tires) It seems that information can be gleaned from the pattern they make on the sidewall as they rotate at higher and higher speeds.
From the outset I knew that the tire had failed because "an old guy" (Jack Crooks #7332) had showed me how to pick up evidence of sudden tire failure at a crash site versus gradual tire failure... or a liar of a driver for example. They thought my diagram was off by 100 feet which is how I got called into the case. Turned out the MPM was misplaced by 100 feet by CAL TRANS.
It was scary how much I didn't know, so I always tried to educate myself by reading the reports of sharp officers and getting my hands on MAIT reports as they came through an office etc.
I read the report on the fatal involving Queen Elizabeth's motorcade for example.
In very olden times we resented MAIT as an interference, but soon realized that they were there to take the heat and pressure off of us in the field in very sensitive investigations. Now I don't see how the department can ever do without MAIT and think that a lot more time needs to be devoted to training field officers on how to properly investigate a collision.