Board debates chip seal vs. slurry seal, authorizes countywide roadway assessment

County staff and supervisors spent an extended portion of the meeting on pavement strategies and prioritization for a multi-year road plan. Engineers described surface-treatment options — including slurry seal, traditional chip seal (DBST/TBST), and fog/fog-seal top coats — and stressed that treatment choice depends on the roadway base condition.

"It depends on the condition of the roadway but what we try to do is finish with the 57 stone which would be the second coat," the county engineer said while describing multi-layer chip-seal methods and safety tradeoffs for applying finer cover aggregate. Participants discussed contractor availability and an illustrative increase in treatment costs (a county route estimate of "70 $80,000" to add a fog seal was raised in the discussion).

Supervisors emphasized prioritization criteria — traffic, crash history, development pressure and engineering condition scores — and asked staff to produce an engineering prioritization to complement supervisor input. The board authorized the county engineer to evaluate every county road and bring back a prioritized list with cost estimates, including suggested criteria for ranking projects.

The assessment will use existing GIS/LiDAR data where available, augmented by on-site engineering judgment. Staff said they will include limited survey/design costs in initiation estimates and will return with project initiation forms for board approval.