Posted on | by Natalie McGuier

This past weekend our intrepid alumni ran the new and ever improving speed trap to gather some very interesting data. The trap was set up just after the monument in the Freeroll, so the posted values should represent terminal buggy speed. Not all the buggy names have been matched to their roll, however rolls are listed in chronological order. We will update the buggy IDs as we figure them out. If you happen to know a given ID, please leave a comment so we can edit appropriately. Some rolls have two MPHs listed because two alumni were independently determining speeds.

We can officially say that PiKA, SDC, and Fringe were consistently the fastest buggies rolling on Saturday. This isn’t terribly surprising given the teams’ histories and what we saw last semester.

Sequence Team ID Movie ID MPH 1 MPH 2
1 CIA  Equinox 126 34.67
2 CIA Impulse 127 31.35
3 SDC Black 128 34.67
4 SDC Avarice 129 31.59
5 SDC Purple 130 33.12
6 Fringe Lt. Blue 131 35.89
7 Fringe 132 30.3
8 Spirit 133 33.12
9 Spirit 134 22.6
10 Spirit
11 Spirit
12 Pika Raptor 135 34.82 35.27
13 Pika Banshee 136 39.15 39.73
14 Apex Apex 137 16.14 16.15
15 CIA Equinox 138 34.38 34.57
16 CIA Impulse 139 31.71 32.31
17 SDC black 140 38.05 37.57
18 SDC Stopped after stop sign before Phipps crosswalk
19 Fringe Blue 141 36.86 37.99
20 Fringe Grey 142 35.57 36.39
21 Fringe Blue 143 33.95 33.89
22 Spirit Grey 144 34.23 34.57
23 Spirit Grey 145 30.41 30.86
24 Spirit Grey 146 31.96 31.14
25 Spirit Grey 147 31.47 31.14
26 Pika Raptor 148 35.11 35.64
27 Pika Banshee 149 38.59 38.84
28 Apex 150 23.71 23.84
29 CIA Equinox 151 34.38 33.89
30 CIA Impulse 152 33.12 32.31
31 SDC Black 153 38.96 39.73
32 SDC Avarice 154 32.6 32.61
33 SDC Purple 155 30.99 30.59
34 Spirit Grey 156 36.86 36.77
35 Spirit 157 32.99
36 Spirit 158 30.99
37 Spirit 159 32.21
38 Spirit 160 31.11
39 Pika Raptor 161 35.27 34.92
40 Pika Banshee 162 38.96 39.28
41 Apex 163 25.1
42 CIA Equinox 164 35.57
43 CIA Impulse 165 32.47
44 SDC Black 166 36.2
45 SDC Avarice 167 33.95
46 SDC Purple 168 32.34
47 Fringe Blue 169 38.41
48 Fringe Grey 170 35.42
49 Fringe Blue 171 32.86
50 Spirit Grey 172 34.23
51 Spirit Grey 173 30.3
52 Spirit into hay bales 174 31.23
53 Spirit Stopped in chute due to wreck
54* Pika Raptor 175 34.52 34.57
55 Pika Banshee 176 35.57 35.64
56 Apex 177 26.74
57 CIA Impulse 178 33.26
58 CIA passing 33.12
59 SDC Black 179 38.41 38.84
60 SDC Avarice 180 33.53
61 SDC Purple 181 32.73
62 Fringe Blue 182 38.78
63 Fringe Blue 183 33.81
64 Spirit 184 35.57
65 Spirit 185 32.09
66 Pika  Raptor 186 36.36
67 Pika  Banshee 187 37.53
68 Apex 188 26.39
69 CIA Equinox 189 37.02
70 CIA Impulse 190 32.99
71 SDC Black 191 38.05
72 SDC Avarice 192 33.95
73 Fringe Blue 193 37.53
74 Fringe Blue 194 33.81
75 Pika Raptor 195 35.57 36.39
76 Pika Banshee 196 36.86 37.57
77 CIA Equinox 197 36.2 37.57
78 CIA Impulse 198 34.82 35.27
79 SDC Avarice  Missed
80 SDC Purple 199 31.71 32.01

11 thoughts on “Timing Data: Feb 28”

  • Elmo Zoneball says:

    Very interesting.

    Is there any sort of validation procedure to assure the device is working properly and the readings are accurate?

    • ben says:

      of the two MPH’s you see, one if from the device, the other is through slow motion camera and frame measurement as the validation.

      I can’t recall which is which, but it looks like the error is overall quite small.

    • Bordick says:

      I think the accuracy is fun, but I am more concerned with the consistency of the data. Do I really care that Banshee is running 39.17 MPH? Nah, I really care that buggy A is outpacing buggy B.

      But yeah, it’s good to see how the system works. I am super thankful for this cool bit of data.

      CIA is doing some fun stuff. Equinox is all over the place.

  • THE SORTER says:

    Sequence Team ID MPH 1
    13 Pika Banshee 39.15
    31 SDC Black 38.96
    40 Pika Banshee 38.96
    62 Fringe Blue 38.78
    27 Pika Banshee 38.59
    47 Fringe Blue 38.41
    59 SDC Black 38.41
    17 SDC black 38.05
    71 SDC Black 38.05
    67 Pika Banshee 37.53
    73 Fringe Blue 37.53
    69 CIA Equinox 37.02
    19 Fringe Blue 36.86
    34 Spirit Grey 36.86
    76 Pika Banshee 36.86
    66 Pika Raptor 36.36
    44 SDC Black 36.2
    77 CIA Equinox 36.2
    6 FringeLt. Blue 35.89
    20 FringeGrey 35.57
    42 CIA Equinox 35.57
    55 Pika Banshee 35.57
    64 Spirit XXXX 35.57
    75 Pika Raptor 35.57
    48 Fringe Grey 35.42
    39 Pika Raptor 35.27
    26 Pika Raptor 35.11
    12 Pika Raptor 34.82
    78 CIA Impulse 34.82
    1 CIA Equinox 34.67
    3 SDC Black 34.67
    54* Pika Raptor 34.52
    15 CIA Equinox 34.38
    29 CIA Equinox 34.38
    22 Spirit Grey 34.23
    50 Spirit Grey 34.23
    21 Fringe Blue 33.95
    45 SDC Avarice 33.95
    72 SDC Avarice 33.95
    63 Fringe Blue 33.81
    74 Fringe Blue 33.81
    60 SDC Avarice 33.53
    57 CIA Impulse 33.26
    5 SDC Purple 33.12
    8 Spirit XXXX 33.12
    30 CIA Impulse 33.12
    58 CIA passing 33.12
    35 Spirit XXXX 32.99
    70 CIA Impulse 32.99
    49 Fringe Blue 32.86
    61 SDC Purple 32.73
    32 SDC Avarice 32.6
    43 CIA Impulse 32.47
    46 SDC Purple 32.34
    37 Spirit XXXX 32.21
    65 Spirit XXXX 32.09
    24 Spirit Grey 31.96
    16 CIA Impulse 31.71
    80 SDC Purple 31.71
    4 SDC Avarice 31.59
    25 Spirit Grey 31.47
    2 CIA Impulse 31.35
    52 Spirit into hay bales 31.23
    38 Spirit 31.11
    33 SDC Purple 30.99
    36 Spirit 30.99
    23 Spirit Grey 30.41
    7 Fringe 30.3
    51 Spirit Grey 30.3
    56 Apex 26.74
    68 Apex 26.39
    41 Apex 25.1
    28 Apex 23.71
    9 Spirit 22.6
    14 Apex Apex 16.14

  • Hauser says:

    I love seeing people collect data about buggy (and love when they share it with me even more), so thanks a lot for this. How similar are the buggies’ paths through the trap? Is there any data on the Hill 2 pushers for any of the rolls?

    Also, the rolls report implied that there was some timing of pushers happening. Are there any numbers on that, or were they just qualitative observations?

    • short fingered vulgarian says:

      I know naught about the speed trap except what was shown in the photos from the other weekend. It looks like a relatively short distance between timing lights/sensors. I agree that the speeds seem overly quick. A 4 mph bias would happen if the timing marks were assumed to be 48 inches apart but were really only 43 inches apart or if the clock was slow by about 0.007 seconds over that distance, or some combination of the two. I believe the results posted are precise but not accurate.

    • Shafeeq says:

      Our trouble is that we have two independent methods of similar precision, but we don’t know how accurate either of them is.
      If anyone has a 3rd source to share, or a buggy-sized object that can move at a known speed, it’d help to calibrate against reality.

      The results make it look like things are more precise than they actually are – the difference between the top 2 times is only one or two raw units of measurement. But once we do the conversion to MPH, it turns into a 0.21MPH difference even though we can’t resolve a difference smaller than that.

      To be off by 4MPH is a 10% error. There’s several sources of error that each could have us consistently 1-2% off, and while it’s possible that they all line up, but I’d be surprised if that turns out to be the case. Clock & distance measurement are the most likely causes for consistent error. I’d be shocked if we mis-measured by more than 1/2″ over 4 feet, but we don’t know the accuracy of the clocks over short time periods.

      The trap next to the haybale near the monument, so every sane buggy gets funneled into the part of the bike lane that isn’t blocked by the haybale, so everybody is taking the same path, shifted at most a couple of feet left to right from each other.

      The sensors all “see” a cone, not a straight line, so the left-right shift matters a little. And depending on the buggy’s shape, it may be detected a little sooner or later. So the distance the buggy actually travels between detections might be different than the measured distance between sensors. The camera method suffers from this both coming and going, since it is using one sensor for both points. But the trap has separate sensors, which should cancel out the error as long as both are equally early or late.

      • Hill-billy-goat-cheese-plate-spinner says:

        The observation is based on many years of race day radar gun measurements. The error could be in that device as well or shared between that system and this system. You might want to check the code to see if there is something delaying establishing the “start” time that is not delaying establishing the “end” time. This seems unlikely, but I have made worse errors in the past.

        Calibration: since you are hopefully detecting the leading edge of the buggies as they pass, you could drive past in a car with a goodly cruise control at steady speed and with a quality GPS to confirm that speed.

        0.2 mph resolution seems more than adequate for this application. A 2nd trap located just below the driveway would have much more utility than trying to eak out 0.1 mph resolution on the one you have.

  • the cook says:

    I used a radar gun of reasonable accuracy for several years and consistently got 36mph for the fastest roll of the day, then several other rolls at 35. Top women’s rolls would read 32 or 33. Eventually this grew tiring as the quality of the turn and pick-up was more important than some fraction of a MPH.

    On at least two occasions a more sophisticated radar gun was used on race days with similar results.

    I very much doubt top speed has increased by 4 MPH especially comparing race day with rolls. If Pika broke off a good one back then it would time just over 50s, only 1 sec at most astray from the fastest ever.

    The difference may be due to slowing at the chute turn, although I could nail the buggy just after the chute flag.

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