Another traffic ticket question

OK, following up on a related recent question, here’s one for the legally inclined types here.

I have heard/read that speed limits are supposed to be based on an engineering survey done on a certain schedule, which analyzes traffic flow through an area and assigns the speed limit at the 85th percentile of the traffic going down a particular stretch of road. If the study is not done, or done improperly, or whatever, this source told me, the basis for the speed limit on that road is not legit, and you can use this to get a speeding ticket on that road thrown out. This is based on the notion that a speeding offence is not “going too fast”, but specifially “going X miles an hour on a road where the limit is Y miles an hour”, and if you prove that Y was not legitimately set as the limit, the ticket is not valid.

So, is this true?
Does this apply in all or most states?
How does one go about getting a copy of the engineering survey for a particular stretch of interstate highway (in Massachusetts)?
Does this kind of defense actually work in court?

I’m no expert, but here’s my WAG:

No.

If you have a nice straight road running through a residential neighborhood where children play, IMHO it doesn’t matter if 99.9% of drivers would tend to drive 50 or 60 mph. Sure, maybe it might have been better to make the road curvy so that you couldn’t go fast, but maybe the road was made in 1850. There are often 25 mph speed limits near schools, for example.

I know that here in Chicago a man tried to challenge a speeding ticket on Lake Shore Drive using such a defense. LSD is a limited access 6 lane divided freeway but the speed limit is 40 or 45 depending on the time of year. He lost.

I think most courts would have the offense read to them as “exceeding the posted speed limit”.

I don’t think they’re going to care about any stinkin’ survey. If the posted limit (the sign) says 35 MPH and the trooper has the gun on you for 50, you lose.

It can & has worked in California. But the only time where I know it works is when a city sets up what amounts to a “speed trap”, such as on Pacific Coast Hwy where a couple little burgs turn the 55MPH speed to 25.

But no, it wouldn’t work in residential districts or school zones or such like.

however- CA is not MA.

Just like that? Wow. Here, it’s common for secondary highways to pass through small villages (the highway often doubles as the main street), and they have a justification to have low limits, but there is nothing trap-like about it. The signs go, over a length of a mile or so, 100kmh, 80kmh zone ahead, 80kmh, 60kmh zone ahead, 60kmh, - little town - , 80kmh, 100kmh…

I think there’d be an outcry if it just dropped in one go like that. It’d be dangerous too.

That’s how it is in Ohio. The speed limits for state roads and highways are set by the state, and the speed limits in cities and villages are set by those municipalities. There is some, but not much, variability depending upon local concerns (i.e. many people complain about people going too fast on their residential street, and city council lowers it even further). In any event, the determinative factor for whether or not you’re exceeding the speed limit is what the sign actually says for that stretch of road.

I’m pretty sure it was done a little less clearly or the court case would have been lost. Around my neighborhood there is an area affectionately known as the “Fowler crawl zone” Where the speed limit drops from 55 to 40 with little evidence of any town and no warning other than if you are paying attention, some cross streets and of course the speed limit sign. The city of Fowler was in desperate financial straits for years and became famous for always having several officers near where the transition existed and citing everyone they could for speeding a little ways beyond the 40mph sign and mercilessly enforcing it to generate fine revenues. The locals all know it and play nice, but its a well traveled stretch especially by agribusiness types who may not know the area well.

The way I heard it was that the study has to be done every five years, or something like that. If it hasn’t been done in the last five years, you can try to get the ticket thrown out on those grounds. I never heard of anyone getting away with it. If someone did, the words would surely spead pretty fast, and I doubt that all streets get such a study done.

Not in any jurisdiction that I have seen.

Nope.

You can probably get whatever surveys were completed with a FOIA request to the agency that has jurisdiction over the specific piece of road in question.

If you could prove that the speed limit was not legitimately established, and that you weren’t exceeding whatever speed limit applies by default, you’d have a chance.

Here’s what I found on MA:

http://www.mass.gov/legis/laws/mgl/90-18.htm

Doesn’t say anything about engineering studies. OTOH, it does establish some requirements for establishing speed limits.

http://www.mass.gov/legis/laws/mgl/90-17.htm

Sets the default rules.

And see, Rules of the Road (pdf p.2).

So long as the signage is in compliance with the MUTCD or Manual on Uniform Traffic Control Devices, I’d pay it and go home. Google MUTCD to learn more.

Here is a model speed zoning law suggested by the National Motorists Association: http://www.ibiblio.org/rdu/nma-zone.html

This seems to be the source of the idea about 85th percentile and repeat survey stuff.

And here is a list of resources from the Reasonable Drivers Unanimous website: http://www.ibiblio.org/rdu/p-sl.html

I’m unaware of any jurisdiction that has adopted the NMA speed zoning law.