Rathdrum staff show speed‑study data supporting 25 mph residential limits; council to consider next steps

City staff presented results from a residential speed study intended to validate the city’s 25‑mph posting in neighborhoods and to identify any streets where posted limits may need adjustment or engineering countermeasures.

The study and findings Staff said the city purchased two speed‑monitoring units in fall 2023 and collected multi‑day speed and volume data on seven single‑family residential neighborhoods. Engineering staff reported a combined 85th‑percentile speed of 24.9 mph across the sampled streets. City staff explained that the 85th‑percentile speed (also called the ‘‘85th’’) is the speed at or below which 85% of vehicles travel; it is a standard traffic‑engineering benchmark used nationwide for setting speed limits.

Why it matters: Idaho law sets statutory standards and minimums for posted speeds; cities that post lower limits must document engineering and traffic studies that justify deviations. Staff said the 85th‑percentile finding supports continuing the 25‑mph limit in residential areas.

Council discussion and enforcement Council members asked whether high measured speeds on specific streets (for example, Bridal Avenue/Bakel Road) would compel an automatic raise in posted limits to match measured 85th speeds, or whether the city should instead pursue traffic‑calming measures (narrowing lanes, geometric changes, signage or other mitigations) to reduce speeds. Staff said the study itself does not mandate raising posted limits; it provides an engineering basis for either retaining current limits or making change after considering physical mitigation and community goals. The city also noted that some special‑condition zones (fronting schools, parks, downtown pedestrian areas) can be separately designated and posted lower speeds as allowed under code.

Next steps and public access Staff will finalize the written report and post it with the meeting packet materials on the city website; they said they will share detailed data with the police department and incorporate council direction on whether to pursue engineering countermeasures or keep current postings. The report in the packet includes average and maximum observed speeds, neighborhood‑level 85th‑percentile calculations, and a map of tested segments.

Ending Council members said they want staff to return with recommended actions for specific streets where measured speeds and conditions suggest a mitigation need. Staff reiterated that the city must follow Idaho statute and standard engineering practice when changing posted speeds and that enforcement rests with police and verified speed limits.