Los Alamos Public Works presents revised Design and Construction Standards to reflect current industry and state manuals

Los Alamos Public Works presented an update Apr. 3, 2025 to the county’s Design and Construction Standards, a document used to guide the design and construction of public improvements and infrastructure within county right-of-way and in private development where public improvements are required.

The update matters because the standards set minimum design, materials and testing expectations for county projects and private development that constructs public improvements. Staff said the revision will supersede the February 2008 edition, clarify references to state and national manuals, and help ensure built infrastructure is consistent with Los Alamos maintenance practices.

Key changes and references Public Works senior engineer Karen Henderson said the updated document was revised in 2024 by the county’s on-call engineering firm (Bohin and Hudson and Company) and reorganized to bring sections up to current industry standards. The revision explicitly references county codes and plans including Chapter 16 (development code), Chapter 14 (floods), Resolution 10-32 (policy for design of public streets and right-of-way), the Los Alamos comprehensive plan, the Bicycle Transportation Plan, the Pedestrian Master Plan, the ADA Transition Plan, the Complete Streets checklist, the Pavement Preservation Policy and the Department of Public Utilities construction standards.

The updated standards also reference external design guides and manuals such as the American Association of State Highway and Transportation Officials (AASHTO) Green Book, the AASHTO guide for bicycle facilities, NACTO guidance, the Manual on Uniform Traffic Control Devices (MUTCD), and New Mexico Department of Transportation (NMDOT) bridge, roadway and drainage manuals. The document incorporates Los Alamos National Laboratory Low Impact Development (LID) standards for stormwater and water-quality structures.

Notable technical changes Staff said they revised hydrology and stormwater management requirements to reference the NMDOT Drainage Design Manual and to emphasize on-site retention and detention to avoid increasing downstream flows. The standards also include scaled minimum testing requirements and special provisions to modify NMDOT testing to suit smaller county projects. A new technical-drawing section will provide standard plan details (for example, valley gutters and ADA sidewalk details) so contractors and designers need not redraw common details for each project. Henderson said a mid-block crossing policy is included in Chapter 3 and will be presented to the board at a future meeting.

Applicability and airport work Board members asked whether the standards apply to airport projects. Staff and board members noted Federal Aviation Administration (FAA) standards apply to airport-specific design; Public Works said where airport work involves common elements such as flat concrete work or asphalt paving the county standards may apply, but airport consultants and FAA requirements will control airport-specific items.

Next steps and availability Public Works said the revised standards are intended to be maintained on the county engineering webpage so referenced documents remain current. Staff said the update gives the county engineer authority to review and enforce standards for private developments that include public improvements. Henderson and staff invited questions and said the standards will be used for upcoming county projects and for plan review of private developments that affect county right-of-way.

— Reporting from the Los Alamos Transportation Board meeting, Apr. 3, 2025.