Thank you for the update. I do think you made the right choice... Sorry I did not get to respond to your comments in time, but just to address -at least- the important points, I will add a few comments of my own.
* Your stating you know where you were LIDARed, and unless you had seen where the officer was located, and used his 1190 feet to measure back, which placed you on the over crossing, then it boils down to "You Did Not Know Where he was or where you were when your speed was measured". No mention was made of you knowing his approximate location was made so I assumed it was unknown! So to make an argument that you were measured in a location that was not surveyed is not likely to get you much!
** Furthermore, and as far as the elevated structure, the speed limit, the limits (start point and end point) of the survey... And my asking you several times whether you would have slowed down or not, it sounds to me like you're answer would have been "yes, I would have slowed down" but not because the conditions were different, not because of traffic signals and not because of heavier traffic... You would have slowed down simply because you were making a turn! So that would have been a moot point...
*** Another reason why I asked you if you would have slowed down is simply because the "advisory speed" and hence the "safe speed" on an elevated structure is usually lower than the segments of the roadway on either end of it. So your claim of "yes, I was at a higher speed on the elevated structure but I would have otherwise slowed down on a normal street" is sort of backwards to the way things typically are. Meaning you should have been driving slower on the elevated structure and may have been able to justify a higher speed on a normal roadway!
**** Last -long- point re the elevated structure is that the rules which apply to setting speed limits on a normal roadway do not apply to elevated structures. So there is no requirement to measure prevailing speeds (no speed survey and no spot speed checks needed).
How do I know that?
California vehicle Code Section 22404. The Department of Transportation or local authority making a determination of the maximum safe speed upon a bridge, elevated structure, tube, or tunnel shall first make an engineering investigation and shall hold a public hearing. Notice of the time and place of the public hearing shall be posted upon the bridge, elevated structure, tube, or tunnel at least five days before the date fixed for the hearing. Upon the basis of the investigation and all evidence presented at the hearing, the department or local authority shall determine by order in writing the maximum speed which can be maintained with safety to the bridge, elevated structure, tube or tunnel. Thereupon, the authority having jurisdiction over the bridge, elevated structure, tube, or tunnel shall erect and maintain suitable signs specifying the maximum speed so determined at a distance of not more than 500 feet from each end of the bridge, elevated structure, tube, tunnel, or any approach thereto.
Let me define an "engineering investigation" (also referred to as "engineering study") is basically an evaluation of the conditions on that segment of the roadway, including particular horizontal and vertical alignment, the number of lanes in each direction, the grade, type of dividing section, sidewalks, pedestrian/bicyclist traffic, roadway design speed... etc. All the factors that make the roadway (in this case a bridge) what it is. [Lets call that Section (1)]
*If* and *WHEN* that is combined with one or more spot speed measurements where prevailing speed of traffic is collected (which usually makes up what is referred to as the "traffic Survey"), then this will make up what we will call Section (2).
Combine section (1) with Section (2) along with a paragraph or two under a “Discussion” header along with a “Conclusion section” and now we have an "Engineering and Traffic Survey"...
If you're only using Section (1) - the "Engineering Study" part - and when combined with a public meeting where the community is informed of the Department of Transportation (Caltrans) and/or local authority is deciding a speed limit for a particular elevated structure, then that speed limit is validated accordingly and is legally justified! So my guess as to the reason why that overpass was included in the survey you had was simply to provide for a way for the local authority to avoid having that segment appear as a “gap with no set speed” on an engineering map of the city!
In other words, your contention that the E &T survey did not measure speeds at or near the elevated structure and as such, the speed limit on that segment is not validated, therefore the prosecution did not rebut the speed trap presumption and that would be your way out of the citation would not have worked in your favor.
***** Last but not least, stating "I have lived here all my life, I know traffic is heavier down there that it is up here" will not work in court. The way to dispute an actual number/count/figure would be to produce evidence to the contrary... Meaning you would have had to contact the D.O.T. or the local Public Works department to see if they had, traffic counts for both, the bridge and the two locations where the spot speed measurements took place, for the period when the survey was conducted. But wait... Even if you were able to obtain those figures, while traffic counts -and as part of the calculations performed during the process of making an E & T survey- may have affected the accident rate which in turn may have impacted speed limit on the roadway segment, it had little or no effect the the speed limit on the bridge... So your claim that traffic volume is different and therefore the speed limit is not set correctly is not a valid assumption!
Don't get me wrong, your case had potential... Although a dismissal will not likely come easy and certainly not at the trial court level. You would have to make certain points during your trial in an effort to preserve some (or at least one) potential issue(s) that will be your grounds for appeal. And yeah, appeals are time consuming, cumbersome and usually require quite a bit on knowledge!