Carroll County transportation staff report higher truck shares, plan hourly data for school-zone counts

Carroll County transportation staff reported that truck percentages at several counting stations increased this year and that 85th-percentile speeds show slight increases since 2023. The committee discussed counts taken on a three-year cycle and concerns about how school-zone reductions affect measured speeds.

The issue matters locally because the committee uses count results to set safety treatments and signal timing near schools and along rural routes. Staff said they are continuing the current count season and will provide hourly breakdowns that separate school-zone periods once counting finishes.

A transportation staff member told the committee the program runs on a three-year cycle with the same yearly stations repeated every three years and that about "15-ish" stations remain to be counted this season. The presenter said they compiled counts at Armory Road dating back to 2014 so the committee could see multi-year changes. The presenter added that the program has removed duplicate or overlapping stations to be more efficient and that the county purchased two new counters this fiscal year and expects to add more next fiscal year because older units are reaching end of service life.

Committee members asked whether counts at the Armory Road station had been separated from school-zone periods. A committee member requested hourly data showing school-zone versus non-school speeds; the transportation staff member said they did not yet separate those counts but would include hourly data for those stations at the end of the count season.

Committee members and staff also discussed measurement metrics. The presenter said the committee looks at the 85th (stated in the meeting as an "80 fifth percentile") as a robust measure of typical higher speeds and noted small increases in that metric at some western stations since 2023. A committee member asked about camera versus tube counters; staff clarified that camera units are often used at intersections while pneumatic tube counters are better for midblock counts.

The committee received an offer from a member to borrow a traffic counter for short-term measures at particular locations. The presenter confirmed that the county can lend equipment and that the typical counters are best for midblock monitoring.

Less-critical technical details discussed included station numbering conventions, school-hour speed limits (presenter noted speeds drop to 20 or 25 during school hours at primary roads), and how changing station placement year-to-year can affect comparability. No formal action was taken; staff committed to producing the requested hourly school-zone breakdowns after the count season concludes.