TPO begins scoping travel‑demand model update; household survey needs 2,000 more responses
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Summary
Staff outlined scoping work for a major travel‑demand model update, discussed tradeoffs in model resolution and run time, and reported the household-travel survey is behind target with about 1,000 recruited and a 3,000-sample goal.
The Knoxville Regional Transportation Planning Organization moved forward on June 23 with scoping for a major update to its travel‑demand model and described the household-travel survey that will feed the update. Staff said the model currently validated to a 2022 base year needs a substantive update and that the MPO will issue a request for proposals once scoping, costs and data needs are finalized.
“It's a mathematical representation of travel demand and supply to help us try to plan for the future,” Mike, the TPO technical presenter, said when describing the region’s travel‑demand model and the reasons for an update. Staff explained the model is a hybrid between a traditional four‑step model and more advanced activity‑based models; the update will trade off model spatial resolution, run time and cost. Staff told the board the study area includes 10 counties (to be reconsidered where Sevier County may have separate modeling efforts) and that a key input to the update is a household-travel survey.
Mike said the household survey has recruited about 1,000 households so far and that the MPO’s target sample is 3,000; because the survey is a scientifically random mail sample, only people who receive the mailed invitation are to complete it. The survey paused for the summer and will resume when schools reopen in August to ensure typical travel patterns are captured. Staff asked elected officials and member jurisdictions to help amplify outreach when the next mailing stage occurs; the MPO said it has an incentive (~$10 per household member) and has partnerships with the University of Tennessee Center for Transportation Research to improve legitimacy and response.
Board members and staff also discussed specific model use cases and data needs: using the model for project prioritization, subarea studies, traffic‑operations and nonmotorized/transit analysis, freight and delivery‑vehicle modeling, tolling and autonomous-vehicle scenarios. Freight data were highlighted as a challenge because much of that information is held by private companies; staff said prior freight committee efforts struggled to obtain private data and that staff would pursue options for a technical report or freight study. Staff gave examples such as delivery-vehicle impacts (ride‑hail and last‑mile deliveries) and the need to consider rail and barge where relevant.
Electrification and emissions modeling were discussed: staff explained the travel‑demand model treats electric vehicles like other motorized vehicles for traffic impacts, while tailpipe‑emissions forecasts are produced in a separate EPA emissions model that includes assumptions about fleet turnover and EV adoption. Board members raised concerns about pavement wear, registration surcharges and funding equity as electric vehicle use grows. Autonomous vehicles also prompted discussion about potential impacts on congestion, parking and regulatory needs; members suggested staff begin tracking deployments in other cities and coordinating with TDOT and state legislators on titling, registration and pilot approaches.
The consultant scoping exercise included a technical workshop and survey of technical‑committee members; staff said consultants will provide cost ballparks for different modeling approaches and recommend a procurement path once survey and scoping results are finalized. The MPO expects to resume the household survey in August and to accelerate outreach to meet the 3,000‑household target this fall.
The board did not take formal action on scoping; staff will use workshop results to define procurement and finalize a request for proposals for the model update.
