Residents object as board approves speed‑zone ordinance affecting Mooney Flat, Donner Pass and Cement Hill

The Nevada County Board of Supervisors voted May 14 to adopt a speed‑zone ordinance that updates posted speeds on three corridors after county traffic engineers presented multi‑day speed studies and collision reviews. The changes cover segments of Donner Pass Road, Mooney Flat Road and Cement Hill Road and implement speed limits set by the California Vehicle Code method (based on the 80th percentile of observed speeds, with limited statutory adjustments).

Engineers explained that, for Mooney Flat, measured speeds in some open stretches met the higher 80th‑percentile thresholds; one segment of Mooney Flat therefore was recommended to be posted at 50 mph (after permitted reductions) while another, more open segment measured higher and would be set at 55 mph consistent with methodology and rounding conventions. Cement Hill would move from the existing 25 mph to 30 mph after applying the CVC rounding and permitted reductions. On Donner Pass Road, staff recommended two lower posted segments (25 mph) where pedestrian/bicycle use and residential density justify reductions and retained 35 mph through other sections.

Multiple residents of Mooney Flat spoke at length in opposition to any increase. They told the board the most densely populated half‑mile of the corridor includes 20 driveways, school bus stops, clustered mailboxes, no shoulders, blind approach intersections and frequent pedestrians, bicyclists and boat trailers headed to nearby recreation sites. Several residents said wildlife and pet strikes are already frequent and said higher posted limits would increase risk. One resident asked that any signage changes or increases be delayed until shoulder, mailbox and sight‑distance work the county plans in 2025 is completed.

Board members and staff acknowledged the technical limits of the speed‑study method — which ties legal limits to observed driver behavior — and noted that artificially posting lower limits contrary to the 80th‑percentile standard can increase speed variance and rear‑end collisions. Supervisors also discussed enforcement limits (CHP resources are constrained) and pledged to pursue practical mitigation measures: improved bus‑stop signage, reflective and cattle warning signs, roadside vegetation trimming and targeted enforcement patrols in peak recreational seasons. County staff said more substantial shoulder and pullout improvements are planned in the next year's road program.

The ordinance passed on a roll call vote. Several residents urged continued engagement with the county engineering and public safety staff and repeated requests for additional mitigation while the community monitors whether the new signs and roadside improvements reduce conflicts.