Matthews staff outlines Transportation Impact Analysis process; council questions effectiveness

Planning staff gave Matthews Town Council a detailed overview of Transportation Impact Analyses (TIAs) on Feb. 24, explaining how the town screens developments and uses TIAs to require off-site and on-site mitigation to lessen traffic impacts.

Susan Lutrick, planning staff, told the council the town adopted the current TIA process in 2021 and has since added collision and multimodal analyses. She said TIAs rely on existing counts, projected regional growth and standard trip-generation rates, and that developers pay the cost of preparing and of third‑party review of TIAs.

The presentation walked the council through the typical steps: a scoping meeting (often using NCDOT worksheets), field counts, capacity and queuing analyses, a build-plus-five-years scenario, collision analysis and multimodal gap assessment. Lutrick said the town asks that recommended mitigations be entered into rezoning notes so recommendations remain visible in design and construction documents.

Council members pushed on whether TIAs ever require developers to reduce a project’s size. Commissioner John Urban said in his 12 years on the dais he could not recall an instance where staff told a petitioner to build fewer units. Lutrick replied that staff cannot direct a developer to reduce unit counts; she said council retains discretion at rezoning to “right size” a project based on the data the TIA provides, and that recent projects have required off‑site improvements such as turn lanes and signals.

Councilmembers raised concerns over trip generation numbers — several said the Institute of Transportation Engineers (ITE) Trip Generation Manual sometimes produces results that do not “pass the smell test” for Matthews. Lutrick said where ITE does not fit a project, NCDOT and the state allow use of local data and that the town’s third‑party reviewers check those calculations.

Lutrick proposed several changes to the town’s TIA guidance: clarify that Transportation Technical Memos must be prepared and sealed by a professional engineer (PE) and reviewed by a third party when necessary; require preparers to attend planning‑board and council hearings to answer questions directly; set expirations (six months for scoping documents and longer for TIAs when conditions change); expand peak‑hour counts to include 30 minutes before and after peak windows; and encourage use of the regional travel model to validate trip distributions.

Council discussed the town’s ability to require mitigation beyond the minimum recommended measures. Lutrick said the town can ask developers for multiple mitigation alternatives and that staff has, in prior cases, negotiated different solutions (for example, tradeoffs of travel lanes for pedestrian refuges) that better fit Matthews’ walkable goals.

Several council members asked staff to study whether loading a developer’s traffic onto current conditions — rather than future background growth — would change mitigation outcomes. Lutrick said the statewide methodology applies background growth and that she and staff are exploring what local adjustments might be reasonable.

Why it matters: The TIA process shapes what transportation infrastructure developers must provide. Council members sought clearer rules on when a TIA justifies larger mitigation, how the town can require better mitigation, and how staff can improve the town’s ability to verify consultant work.

What’s next: Lutrick asked council whether staff should pursue the proposed clarifications and the board discussed directing staff to draft specific manual changes to present at a later meeting.