Can an Officer Assigned to Desk Duty Still Testify in Traffic Court

[cdwjava]

I do often see a pair of what look like air hoses across the street about 12" apart which were laid with precision that are connected to a metal box, obviously for recording something. This could be the official road survey, yes?

That could be, yes. It might also be for some other speed purpose.

There are some grants that require speed surveys before and after enforcement periods, and we will use the same method to monitor the effects of targeted enforcement for the grant or other purposes. So, while that is one of the reasons the "hoses" might be out there, it does not automatically mean that it is THE speed survey.

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As a side note, I don’t know of any law enforcement agency that performs traffic surveys for the purpose of radar enforcement. In addition to is being a conflict of interest, such duties fall outside the primary mission of law enforcement and most police officers lack the expertise, training and background necessary to perform a function that is normally carried out by traffic/highway engineers.

Correct. The most involvement law enforcement will likely have would be to request an updated speed survey so that they can conduct radar enforcement. I don't know of any agency that has the luxury of hiring or contracting their own traffic engineer and the equipment.

[trafeng]

Most jurisdictions gather speed and volume for various roads on a continuing basis. As mentioned, this is done for a broad range of reasons; sometimes related to signal operation and timing, or new development or pavement management etc. Most counting equipment can also capture speeds if that is the intent of the study; but that's not always the method used. Many agencies use hand held radar guns and a limited sample size. In any case, the 85th percentile speed is only one of several factors used to establish speed limits. For additional information, go to the Institute of Transportation Engineers website; www.ite.org There is enough information there to put you into a coma if your not careful.

I'm not aware of any agency that would use a radar speed trailer for a speed study. Some of those are capable of gathering speed data, but by their very nature they are intended to affect speed (hopefully lower it) so any data they collect would only be useful in determining their own effectiveness, and not for a valid speed study. Their use for a speed study sounds like an urban legend; up there with "Police make tons of money from writing tickets" and "stop signs fix any traffic problem".

[cdwjava]

Trafeng,

Thank you for the post and the link.

I agree that there is a lot of misinformation on the issue and there have been people that feel that speed surveys (for purposes of establishing speed limits) are ongoing and done in all manner of nefarious ways. In my career in my current city they have done each roadway once - and that was at MY prompting as the existing surveys were woefully out of date. I found that the city had been arbitrarily lowering speed limits without supporting surveys in an attempt to affect traffic safety, but in doing so they rendered enforcement nearly impossible. So, we had to change that.

[BrianGC]

Trafeng,

Thank you for the post and the link.

I agree that there is a lot of misinformation on the issue and there have been people that feel that speed surveys (for purposes of establishing speed limits) are ongoing and done in all manner of nefarious ways. In my career in my current city they have done each roadway once - and that was at MY prompting as the existing surveys were woefully out of date. I found that the city had been arbitrarily lowering speed limits without supporting surveys in an attempt to affect traffic safety, but in doing so they rendered enforcement nearly impossible. So, we had to change that.

The only reason I suspected speed surveys were being done in 'nefarious' ways is because I was told that by more than one police officer. I had no reason to think they were incorrect. But what made me suspect that it was not true is that I have never heard of defense attorneys challenging the legitimacy of the 85th percentile figure as being determined by corrupted means. Posting a "your speed is" digital readout showing your speed would be clearly corrupting the 85th percentile data. It could easily be challenged and impeached by attorneys.

But if you think about how it is done now with supposedly unmarked vehicles, it also has a manipulated nature about it. Vehicle speed is usually determined by the posted speed limit. If you want a true 85th percentile of that road then take down the posted speed limit signs for about a year and do not do speed enforcement on that road for that same time period. Then take the speed survey when the traffic has established their own 'safe speed' irrespective of posted speed limtis.

By lowering a speed limit and leaving that sign posted, it will affect any speed survey taken after that.