Night averages >30 mph
51.9%
4,113 of 7,920 · 10 PM–6 AM
Traffic monitoring report · Device 305290
Main Street,
Clarkston.
March 31–April 24, 2026
One monitoring location · 30 mph posted limit
Monitoring window25calendar dates
First and last days are partial
First and last days are partial
Average >30 mph
11,111
15.0% of all recorded passages
Night / day above-30 rate
4.9×
51.9% at night · 10.6% by day
Recorded passages
74,040
One location · repeat trips included
What the monitor recorded
More than half averaged
above 30 mph at night.
4,113 above-limit passages at night. From 10 PM to 6 AM, 51.9% of 7,920 passages averaged above 30 mph: about 4.9 times the daytime rate.
11,111 across the full period. That is 15.0% of all recorded passages over 25 monitored dates. Counts include repeat trips.
The nighttime mean was above 30 mph. Nighttime passage averages had a mean of 30.7 mph, compared with 22.3 mph during the day.
Across the full period, 85% averaged 30 mph or less and the mean was 23.2 mph. Those combined figures do not describe the much higher nighttime above-limit rate.
Corrected October 4: the posted limit is 30 mph. The export’s violation counts exactly match its above-30-mph average-speed bins on all 25 dates. Earlier materials incorrectly used 35 mph. These comparisons describe each passage’s recorded average speed; a passage’s peak may be higher.
01 / Time of day
Nearly five times
the daytime above-limit rate.
Nighttime: 51.9%. Daytime: 10.6%. Both bars use the same 0–100% scale. Daytime had more traffic and more above-limit passages in total: 6,998 versus 4,113.
Nighttime
10 PM–6 AM51.9% averaged above 30 mph
4,113 averaged above 30 mph / 7,920 recorded passages
Mean recorded speed: 30.7 mph
Daytime
6 AM–10 PM10.6% averaged above 30 mph
6,998 averaged above 30 mph / 66,120 recorded passages
Mean recorded speed: 22.3 mph
Every hour has a different pattern
Two aligned charts separate traffic volume from the share averaging above 30 mph.
Shaded hours: 10 PM–6 AM. Hourly volume is the average across all 25 monitored dates, including the two partial days.
02 / Daily & weekly patterns
See the variation across the period.
Compare complete days with care: March 31 and April 24 contain partial-day recordings.
Daily traffic
Recorded average speeds: dark bars at or below 30 mph; orange bars above 30 mph. Asterisks mark partial days.
Day of week
Weekday share averaging above 30 mph: 14.1%. Weekend share: 18.1%.
Each weekday appears three or four times. Tuesday and Friday include a partial day. This is a description of this reporting period.
03 / Every hour, every day
Look closer at the pattern.
Each cell represents one hour. Select a cell for its passage count, above-30 count, mean and peak.
Share averaging above 30 mph
Select a cell to see the recorded observations.
Gray cells have no recorded passages. A high percentage may describe a small count; check the selected cell’s denominator. Times follow the device export.
04 / Recorded speeds
An average and a maximum
answer different questions.
Mean recorded speed
23.2 mph
A passage-weighted average
Sum of the export’s per-passage average speeds divided by recorded passages. It does not show the full spread of speeds or establish speed-limit compliance.
Highest recorded peak
77 mph
One interval’s maximum
April 24, 06:00–06:30. The interval contained 75 passages, including 25 passages averaging above 30 mph. A recorded maximum is not a typical-speed estimate.
Intervals with a high recorded peak
Among 1,122 thirty-minute intervals containing recorded passages.
45+ mph159 intervals
14.2% of nonempty intervals
50+ mph44 intervals
3.9% of nonempty intervals
55+ mph15 intervals
1.3% of nonempty intervals
60+ mph6 intervals
0.5% of nonempty intervals
These are interval counts, not counts of vehicles at each speed. Thresholds overlap: an interval with a 60+ mph peak also appears in the 45+, 50+ and 55+ groups. Bars use a common 0–100% scale.
05 / Thirty-minute detail
Keep exceptional readings
in context.
Times are interval starts. “Above 30” counts passages whose recorded average exceeded 30 mph. Rate rankings include only intervals with at least 30 recorded passages.
Ten highest recorded peaks
All dates are in 2026. Peak is the interval maximum.
| Date | Start | Peak (mph) | Passages | Above 30 |
|---|---|---|---|---|
| 04-24 | 06:00 | 77 | 75 | 25 |
| 04-13 | 21:00 | 69 | 62 | 15 |
| 04-01 | 12:00 | 69 | 99 | 12 |
| 04-05 | 23:00 | 69 | 22 | 12 |
| 04-22 | 21:30 | 62 | 72 | 18 |
| 04-23 | 00:00 | 60 | 17 | 10 |
| 04-14 | 23:00 | 58 | 36 | 21 |
| 04-12 | 01:00 | 58 | 20 | 12 |
| 04-15 | 17:30 | 57 | 100 | 8 |
| 04-17 | 12:00 | 57 | 107 | 6 |
Ten highest above-30 rates
Minimum denominator: 30 recorded passages.
| Date | Start | Above 30 (%) | Passages | Above 30 |
|---|---|---|---|---|
| 04-01 | 05:00 | 81.6 | 38 | 31 |
| 04-10 | 23:30 | 72.3 | 47 | 34 |
| 04-18 | 00:00 | 71.1 | 38 | 27 |
| 04-08 | 22:30 | 70.8 | 48 | 34 |
| 04-23 | 05:30 | 70.7 | 41 | 29 |
| 04-01 | 23:30 | 69.7 | 33 | 23 |
| 04-21 | 05:00 | 69.7 | 33 | 23 |
| 04-16 | 05:30 | 69.2 | 39 | 27 |
| 04-13 | 05:00 | 67.7 | 31 | 21 |
| 04-07 | 22:30 | 67.6 | 37 | 25 |
These are selected extremes, not a representative sample. Above-30 counts use each passage’s recorded average speed; peak is the interval maximum.
06 / Complete daily detail
All 25 monitored dates.
The table keeps the count, rate, average and maximum together.
Daily observations
| Date (2026) | Day | Passages | Above 30 | Above 30 (%) | Mean (mph) | Peak (mph) |
|---|---|---|---|---|---|---|
| Full period | 74,040 | 11,111 | 15.0 | 23.2 | 77 | |
* Partial day. The period’s mean and percentage are weighted by passages; they are not simple averages of daily values.
07 / Source & method
What is counted.
What can be concluded.
Source and coverage
- Monitor
- Radar monitor 305290, Main Street, Clarkston.
- Reporting window
- March 31–April 24, 2026: dates with recorded traffic in the export. First and last days are partial. These boundaries do not establish physical installation or removal dates.
- Source resolution
- 30-minute intervals. Hourly and daily views aggregate those intervals. Times are shown as recorded; no timezone conversion is applied.
- Counts
- Recorded vehicle passages, including repeat trips. The export does not identify unique drivers.
Calculation notes
- Above the limit
- The CSV’s #violators field exactly matches its average-speed bins above 30 mph on all 25 dates. Rate = these passages ÷ all recorded passages. Robert confirmed the 30 mph posted limit.
- Average versus peak
- A passage’s recorded average may be at or below 30 mph while its peak exceeds 30. The 85% figure refers to averages. It does not mean those passages never exceeded the limit.
- Mean and peak
- Mean = export’s sum of average speeds ÷ passage count. Peak = the largest recorded interval maximum. Neither is a percentile speed.
- Time groups
- Daytime: 06:00–21:59. Nighttime: 22:00–05:59. Weekends: Saturday and Sunday.
Data check and interpretation limits
All 25 daily violation totals reconcile exactly with the above-30-mph average-speed bins: 11,111 in total. This infers the reporting cutoff from the export; it does not recover the sign’s flashing or display settings. Download the daily reconciliation. Bin definitions: Radarsign StreetSmart, page 2.
There is no before-and-after comparison or control location. This dataset cannot establish that the sign reduced speeding or explain why speeds differ. It does not measure crashes, near misses or congestion, and does not determine overall road safety. Speed readings are reported from radar monitor 305290’s original 30-minute CSV export.
Source file: 305290_DS_20260301_20260429_30.csv
Interactive report and source files: https://slow-the-fox-down-main-street.pages.dev/report