Jefferson County officials tell Arvada council parkway remains embedded in regional plans; council raises contamination and funding concerns

Jefferson County transportation staff told the Arvada City Council on Dec. 9 that the proposed Jefferson Parkway remains included in regional travel and air‑quality models and that removing the project from those plans would require a multi‑step, months‑long update by the Denver Regional Council of Governments (DRCOG).

"The parkway is included in our 2050 projections," said Christina Lane, transportation operations and planning manager for Jefferson County, as she walked council through alignment maps and DRCOG focus‑model results. Lane told the council that earlier modeling used by some consultants underestimated future volumes — for example, an older 2015 focus model showed roughly 26,000 vehicles per day on State Highway 93 at 64th, while the 2050 focus model projects about 45,000 vehicles per day at the same location.

Why it matters: Lane said the DRCOG focus model drives assumptions local agencies use to assess traffic and air‑quality impacts. If the parkway were removed from DRCOG's planning assumptions, regional modeling and air‑quality projections would be reworked — a process she estimated could take about six to nine months and still require state and federal reviews.

Lane also framed the parkway as a regional beltway gap‑closure, not just a capacity fix. She emphasized potential benefits that include reduced vehicle miles traveled on local streets, improved emergency egress and response time in wildfire‑vulnerable areas north of North Table Mountain, and potential multimodal connections to future passenger‑rail corridors.

Council concerns and follow-up requests: Several council members asked for more recent origin‑destination and projection data and for local plans to be included explicitly in DRCOG inputs. Council member Griffith asked whether planners can estimate how much of the parkway's traffic would be through‑traffic versus local trips; Lane said DRCOG maintains O–D data that could be used for that analysis.

Council member Ambrose pressed the county on environmental safeguards near the Rocky Flats area, asking whether construction could disturb legacy contamination and whether building a roadway would effectively cap or spread contaminated soils. "Breathing it in is what causes cancer issues," Ambrose said as she urged caution. Council member Pfeiffer said the Colorado Department of Public Health and Environment (CDPHE) has soil‑testing results and asked staff to re‑share the report; staff later confirmed they sent the CDPHE document to council members during the meeting.

Funding implications: Pfeiffer warned that removing the parkway from regional assumptions could affect regional scoring and funding eligibility for other projects. Lane acknowledged the modeling and funding linkages and said any re‑modeling could change allocations and would likely reassign some costs for corridor improvements to local agencies.

Numbers and near‑term steps: Lane flagged that some parkway designs and interchange concepts are more fully developed (her office has advanced interchange designs), while other connecting segments remain conceptual. She said DRCOG is updating its focus model now and has requested local comprehensive‑plan inputs; the regional transportation plan also routes proceedings to DRCOG committees and, ultimately, to state and FHWA review if changes are pursued.

No formal council action was taken; the presentation closed with staff pledging to share DRCOG inputs and the CDPHE soil‑testing report and to coordinate further analysis with county and regional partners.