Chris Davidson's Zapruder film Re-enactment.

[Chris Davidson]

When you create speed and distance reductions, you have to adjust frame counts too:
One reason why the WC created different versions of CE884, with the same physical locations (z161/168 - z166/171) applied to different frame numbers.

The adjustments were not reflective of the limo traveling at those speeds (2.24/3.734) at zframes (z161/168 - z166/171), they are a reflection of the reduction in speed applied to the limo.

[Chris Davidson]

The diorama along with other supplied WC documents provides a distance to work with:

[Chris Davidson]

Remember, it's not how fast the limo was moving, it's what the limo's speed was reduced to in terms of frame count. Such as the following:
zframe 168-z171 was entered as a distance of .9ft traveled.
Extend that over 1 second of time:
18.3/3 = 6.1 x .9ft = 5.49ft traveled
30ft distance via the diorama / 5.49ft per sec = 5.464sec duration
5.464sec x 18.3frames per sec = 100 frames
while:
zframe161-166 was also entered as a distance of .9ft
Extended over 1 sec:
18.3/5 =3.66 .9ft = 3.294ft traveled
30ft distance via the diorama /3.294ft per sec = 9.107...sec
9.107..sec x 18.3 frames per sec = 166.66... frames

[Chris Davidson]

How might the (z168-z171=3.734mph) reduction appear in other parts of the film, look toward the headshot:
The plat (at 1"=10ft) has the limo at z301 using Moorman's inner left foot through JFK and onto Z = approx 7.2ft traveled onto z313
Using 1 second: 18.3/12 = 1.525 x 7.2ft = 10.98ft per sec / 1.47 = 7.469mph
The average speed (slip up by Shaneyfelt) is referred to as 11.2mph.
What was the average speed reduced by in terms of mph to get to the limo's speed from Z301-z313?
Does that answer ring a bell?
What is the ratio of 7.469/11.2?
What is the ratio of 3.734/11.2?
Mr. SPECTER. Is that a constant average speed or does that speed reflect any variations in the movement of the car?
Mr. SHANEYFELT. That is the overall average from 161 to 313. It does not mean that it was traveling constantly at 11.2, because it was more than likely going faster in some areas and slightly slower in some areas. It is only an average speed over the entire run.

[Chris Davidson]

Remember, it's not how fast the limo was moving, it's what the limo's speed was reduced to in terms of frame count. Such as the following:
zframe 168-z171 was entered as a distance of .9ft traveled.
Extend that over 1 second of time:
18.3/3 = 6.1 x .9ft = 5.49ft traveled
30ft distance via the diorama / 5.49ft per sec = 5.464sec duration
5.464sec x 18.3frames per sec = 100 frames

A 100 frame adjustment?
Governor CONNALLY. As we looked at them this morning, and as you related the numbers to me, it appeared to me that I was hit in the range between 130 or 131, I don't remember precisely, up to 134, in that bracket.
Mr. SPECTER. May I suggest to you that it was 231?
Governor CONNALLY. Well, 231 and 234, then.
Mr. SPECTER. The series under our numbering system starts with a higher number when the car comes around the turn, so when you come out of the sign, which was----
Governor CONNALLY. It was just after we came out of the sign, for whatever that sequence of numbers was, and if it was 200, I correct my testimony. It was 231 to about 234. It was within that range.

[Chris Davidson]

Actually, it all started with this:
The limo traveling 2.24(public version CE884) or 3.74mph(CE884 version on final WC plat may1964) below.

The diorama provided a distance for us.

Does this CE884 version reflect a continuation of data previous to z168 and back to Position A where Position A = Zframe# ?
Using the provided WC documentation, this creates a distance of 50.7ft between z168 and Position A.
From z168-z171, the limo speed is .3ft per frame = 3.734mph =5.49ft per sec
169frames x .3ft per frame = 50.7ft
Was the limo traveling 3.734 mph for that 50.7ft?

[Chris Davidson]

Actually, it all started with this:

What does the reduction in limo speed look like from z168-z186(red box entries).
I like converting to seconds of time:
18.3/18 = 1.01666... x 21.6ft(distanced traveled z168-z186) = 21.96ft per sec/1.47(1mph) = 14.938mph
14.938mph - 3.734mph = 11.2mph = Shaneyfelt average
14.938/2 = 7.469mph = limo speed from z301-z313
Notice a theme reoccurring throughout.