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Radar Recorder
Data Comparison vs. TRAX Flex
Data Comparison vs. TRAX Flex
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To compare the accuracy of the Radar Recorder against a road tube
recorder, the Radar Recorder was set up to record data at the same
location as a TRAX Flex HS recorder - a two-lane, bidirectional road
with average daily traffic of approximately 8,000 vehicles.
The clocks of both the Radar Recorder and TRAX Flex were synchronized to the same time and date at the
start of the study. The resulting data from the TRAX Flex was processed with the TRAXPro software and
compared with the data from the Radar Recorder, which was processed using the VDA2 software.
Below are some details of this comparison for a 24-hour period. If you would like to do further analysis of the
data, you can download a PDF of this analysis data, which contains the actual reports from both TRAXPro and
VDA2, Radar Recorder vs. TRAX Flex Data Comparison.pdf.
recorder, the Radar Recorder was set up to record data at the same
location as a TRAX Flex HS recorder - a two-lane, bidirectional road
with average daily traffic of approximately 8,000 vehicles.
The clocks of both the Radar Recorder and TRAX Flex were synchronized to the same time and date at the
start of the study. The resulting data from the TRAX Flex was processed with the TRAXPro software and
compared with the data from the Radar Recorder, which was processed using the VDA2 software.
Below are some details of this comparison for a 24-hour period. If you would like to do further analysis of the
data, you can download a PDF of this analysis data, which contains the actual reports from both TRAXPro and
VDA2, Radar Recorder vs. TRAX Flex Data Comparison.pdf.
| 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 |
Total Volume
| 11 1 5 0 6 24 109 145 131 119 135 183 267 173 169 301 576 800 413 166 110 70 35 21 |
| 11 1 5 0 6 24 111 153 131 117 140 184 266 173 172 301 577 803 415 167 110 71 34 21 |
| 10/17/2007 |
| TRAX Flex |
| Radar |
| Difference |
| 0 0 0 0 0 0 +2 +8 0 -2 +5 +1 -1 0 +3 0 +1 +3 +2 +1 0 +1 -1 0 |
| 7 4 0 2 14 64 269 704 619 259 147 173 212 245 191 222 234 217 172 122 100 76 28 20 |
| 7 4 0 2 14 64 273 705 617 263 147 177 219 248 202 224 246 233 178 122 100 77 26 20 |
| 0 0 0 0 0 0 +4 +1 -2 +4 0 +4 +7 +3 +11 +2 +12 +16 +6 0 0 +1 -2 0 |
| 18 5 5 2 20 88 378 849 750 378 282 356 479 418 360 523 810 1017 585 288 210 146 63 41 |
| 18 5 5 2 20 88 384 858 748 380 287 361 485 421 374 525 823 1036 593 289 210 148 60 41 |
| 0 0 0 0 0 0 +6 +9 -2 +2 +5 +5 +6 +3 +14 +2 +13 +19 +8 +1 0 +2 -3 0 |
| TRAX Flex |
| Radar |
| Difference |
| TRAX Flex |
| Radar |
| Difference |
| Total |
Eastbound Lane
Westbound Lane
Combined
| 3970 |
| 3993 |
| +23 (0.5%) |
| 4101 |
| 4168 |
| +67 (1.6%) |
Analysis: Over a 24 hour period, the Radar Recorder data compares extremely well with that of the TRAX Flex,
both over individual lanes and as a total. Overall volumes recorded by the Radar Recorder were within 1.1% of
those from the TRAX Flex.
It should also be noted that typically a road tube recorder will miss a few vehicles during peak times, due to
vehicles in opposite lanes hitting the tubes at the same time. In reviewing the above data, one of the main times
where the Radar Recorder over counted the TRAX was at peak times (7:00 AM (+9), 5:00 PM (+19)), which may
indicate that the Radar Recorder volumes are more accurate than those of the TRAX for these time periods. At
times of the lowest volumes (12 AM to 5 AM) the two units were identical in their recordings.
both over individual lanes and as a total. Overall volumes recorded by the Radar Recorder were within 1.1% of
those from the TRAX Flex.
It should also be noted that typically a road tube recorder will miss a few vehicles during peak times, due to
vehicles in opposite lanes hitting the tubes at the same time. In reviewing the above data, one of the main times
where the Radar Recorder over counted the TRAX was at peak times (7:00 AM (+9), 5:00 PM (+19)), which may
indicate that the Radar Recorder volumes are more accurate than those of the TRAX for these time periods. At
times of the lowest volumes (12 AM to 5 AM) the two units were identical in their recordings.
| 8071 |
| 8161 |
| +90 (1.1%) |
85th Percentile Speeds
The 85th percentile speed is a standard value used in many speed data reports, and is derived from the speeds
of all vehicles that are recorded. Note that in TRAXPro, speeds are reflected in whole numbers while VDA2 uses
decimals. Also note that the 85th percentile is not always computed if the volumes are too low. These are shown
with an asterisk.
of all vehicles that are recorded. Note that in TRAXPro, speeds are reflected in whole numbers while VDA2 uses
decimals. Also note that the 85th percentile is not always computed if the volumes are too low. These are shown
with an asterisk.
| 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 |
| 50 46 55 * 42 49 48 47 48 48 47 48 48 49 48 47 45 44 45 46 47 49 49 48 |
| 50.6 * * * * 49.9 48.8 47.5 48.7 48.5 47.7 48.8 47.8 48.9 48.7 47.9 45.9 44.9 45.1 46.9 47.7 50.4 49.7 48.9 |
| 10/17/2007 |
| TRAX Flex |
| Radar |
| Difference |
| 0.6 * * * * 0.9 0.8 0.5 0.7 0.5 0.7 0.8 0.8 0.9 0.7 0.9 0.9 0.9 0.1 0.9 0.7 1.4 0.7 0.9 |
| 50 46 * 42 51 49 46 44 47 48 48 49 48 47 48 49 48 49 49 49 47 49 49 50 |
| * * * * 52 49.4 45.6 44.8 46.5 48.1 48.9 48.3 48.1 47.1 47.9 48.6 48.7 48.9 49 49.6 47.9 49.3 48.7 50.2 |
| * * * * 1 0.4 0.4 0.8 0.5 0.1 0.9 0.7 0.1 0.1 0.1 0.4 0.7 0.1 0 0.6 0.9 0.3 0.3 0.2 |
| 50 47 55 42 49 49 47 45 47 48 48 49 48 48 48 48 47 45 46 48 47 49 49 49 |
| 50.7 * * * 49.8 49.6 46.7 45.2 47.1 48.3 48.4 48.6 48 48 48.3 48.3 47.1 45.5 45.8 48.3 47.9 50 49.6 49.6 |
| 0.7 * * * 0.8 0.6 0.3 0.2 0.1 0.3 0.4 0.4 0 0 0.3 0.3 0.1 0.5 0.2 0.3 0.9 1 0.6 0.6 |
| TRAX Flex |
| Radar |
| Difference |
| TRAX Flex |
| Radar |
| Difference |
| Total |
Eastbound Lane
Westbound Lane
Combined
| 47 |
| 46.9 |
| 0.1 |
| 48 |
| 47.6 |
| 0.4 |
| 47 |
| 47.3 |
| 0.3 |
Analysis: Over a 24 hour period, the 85th percentile speeds of the Radar Recorder and the TRAX Flex were
virtually identical. The data above shows that inner lane was within 0.1 mph while the outer lane was within 0.4.
Combined, after recording more than 8000 vehicles, the TRAX data shows 47 mph while the Radar shows 47.3,
which, from a statistical standpoint, is just about a perfect match.
virtually identical. The data above shows that inner lane was within 0.1 mph while the outer lane was within 0.4.
Combined, after recording more than 8000 vehicles, the TRAX data shows 47 mph while the Radar shows 47.3,
which, from a statistical standpoint, is just about a perfect match.