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VMT SCREENING MAPS
The following Screening Map provides the VMT per capita of the Traffic Analysis Zones (TAZ) for Residential Uses within the City of Calistoga. Figure 1 illustrates the VMT per Capita in the City of Calistoga by TAZ.
TAZs shown in Light Green and White depict a VMT Threshold at or below 85% of the Countywide average (e.g. at or below 12.05 VMT per capita). Potential residential projects located in Light Green or White are considered to be screened out and no further VMT Analysis is necessary.
TAZs shown in Yellow, Orange, or Red depict a Daily VMT Threshold above 85% of the Countywide average (e.g. above 12.05 VMT per capita). Potential residential projects located in Yellow, Orange, and Red do not qualify to be screened out, and require a VMT Analysis.
Figure 1. Screening Map for Residential Uses
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The following Screening Map provides the VMT per Employee of the Traffic Analysis Zones (TAZ) for Employment uses within the City of Calistoga. Figure 2 illustrates the VMT per Employee in the City of Calistoga by TAZ.
TAZs shown in Gray depict a Daily VMT Threshold at or below 85% of the Countywide average (e.g. at or below 18.70 VMT per employee). Potential projects containing Employment Uses in Gray are considered to be screened out, and no further VMT Analysis is required.
TAZs shown in Light Green depict a Daily VMT Threshold above 85% of the Countywide average (e.g. above 18.70 VMT per employee). Potential projects containing Employment Uses located in Light Green do not screen out, and a VMT Analysis is required.
Figure 2. Screening Map for Employment Uses
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MITIGATING VMT IMPACTS
Projects that do not qualify under the VMT Screening Criteria would be required to prepare a project specific VMT Analysis. For projects that would result in a potentially significant VMT impact, feasible, quantifiable and implementable measures to mitigate impacts would be required to offset or reduce VMT impacts. As set forth in the Technical Advisory on Evaluating Transportation Impacts In CEQA, the following measures can potentially be relied upon to reduce vehicle miles traveled to various extents. The effectiveness of each mitigation measure in the context of the project would need to be analyzed and included as part of the project’s VMT analysis:
• Improve or increase access to transit.
• Increase access to common goods and services, such as groceries, schools, and daycare. • Incorporate affordable housing into the project.
• Incorporate neighborhood electric vehicle network.
• Orient the project toward transit, bicycle and pedestrian facilities. • Improve pedestrian or bicycle networks, or transit service. • Provide traffic calming.
• Provide bicycle parking.
• Limit or eliminate parking supply.
• Unbundle parking costs.
• Provide parking or roadway pricing or cash-out programs. • Implement or provide access to a commute reduction program. • Provide car-sharing, bike sharing, and ride-sharing programs. • Provide transit passes.
• Shifting single occupancy vehicle trips to carpooling or vanpooling, for example providing ride-matching services.
• Providing telework options.
• Providing incentives or subsidies that increase the use of modes other than single-occupancy vehicles. • Providing on-site amenities at places of work, such as priority parking for carpools and vanpools, secure bike parking, and showers and locker rooms.
• Providing employee transportation coordinators at employment sites. • Providing a guaranteed ride home service to users of non-auto modes.
Further guidance on selecting and combining VMT reduction measures is presented in the California Air Pollution Control Officers Association’s Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity (Handbook), Final Draft dated October 2024. The following shows the types of transportation measures that may be relied upon in VMT Analysis. Refer to the Handbook for guidance on selection measure, combining measures, and quantifying VMT reductions.
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REFERENCES
1. Technical Advisory On Evaluating Transportation Impacts In CEQA, prepared by California Governor’s Office of Planning and Research, December 2018.
2. Vehicle Miles Traveled-Focused Transportation Impact Study Guide, prepared by Caltrans, May 20, 2020.
3. CEQA Transportation Impacts (SB 743) Key Documents and Links, provided by California Governor’s Office of Land Use and Climate Innovation, March 2025. CEQA: Transportation Impacts (SB 743) - Office of Land Use and Climate Innovation
4. Association’s Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity, prepared by California Air Pollution Control Officers, Final Draft dated October 2024.
5. Napa Valley Countywide Transportation Plan: Advancing Mobility 2045, prepared by Napa Valley Transportation Authority, May 2021.
6. Napa County Regional Climate Action and Adaptation Plan: Greenhouse Gas Reduction Framework, Guidelines, and Preliminary GHG Reduction Measures, prepared by Ascent Environmental, June 14, 2024.
7. Calistoga Active Transportation Plan, adopted by the City of Calistoga, October 21, 2014
8. City of Calistoga Climate Action Plan, adopted by the Calistoga City Council, April 1, 2014.
9. Napa Countywide Bicycle Plan, prepared by Napa Valley Transportation Authority, September 2019.
10. Napa Countywide Pedestrian Plan, prepared by Napa Valley Transportation Authority, August 2016.
11. Napa County Short Range Transit Plan, prepared by Napa Valley Transportation Authority, 2023- 2028.
ATTACHMENTS
1. Definitions
2. Methodology
3. NVTA Background Information on VMT Rate Calculations
4. TJKM Memo
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Attachment 1: Definitions
Affordable Housing Projects
Affordable housing in infill locations generally improves jobs-housing balance, shortening commutes and reducing VMT. Given the relatively low citywide rate for residential VMT in Calistoga (which is well below the countywide average) and proximity to employment in the hospitality industry: it is recommended that 100 percent affordable housing projects in infill locations be presumed to have a less than significant VMT impact, consistent with OPR guidance.
Hotel Projects in Low-VMT Areas
Hotel projects in areas where the rate of VMT per Employee does not exceed 85 percent of the Countywide average (based on the NVTA screening tool as shown on Figure 2) may be presumed to have a less than significant VMT impact, provided that VMT attributable to hotel guests is not anticipated to result in a significant increase in total VMT.
Local-serving Retail Projects
Retail projects that are less than 30,000 square feet may be presumed to have a less than significant VMT impact if the retail is locally serving (including retail projects that would serve local hotel guests). This is based on the OPR recommendations that VMT impacts associated with customer-serving uses should be based on whether the project results in a net increase in total VMT. OPR guidelines note that retail projects typically re- route travel from other retail destinations, and therefore a retail project may lead to increases or decreases in VMT, depending on previously existing travel patterns. Similarly, a large share of retail trips are “pass-by trips” that would not generate VMT attributable to a retail project.
Residential & Employment Uses in Low-VMT Areas
Based on OPR guidance, residential or employment-oriented projects in low-VMT areas may be presumed to have less than significant VMT impacts and would not require further VMT analysis. The NVTA screening map tool shows low-VMT areas where residential or workplace VMT does not exceed 85 percent of the Countywide average:
• Residential Uses: Residential projects proposed for sites within the boundaries of areas with average rates of VMT per Capita that do not exceed 85 percent of the countywide average, as illustrated on Figure 1, can be assumed to have a less than significant VMT impact. Such projects would not require further VMT analysis, provided the proposed residential development provides similar multi-modal access provisions as existing residential development in the area.
• Employment Uses: Commercial projects where most daily trips would be generated by on-site employees (not customers), such as proposed office developments, can be presumed to have a less than significant VMT impact and would not require further VMT analysis if proposed for sites within areas with average VMT per Employee that does not exceed 85 percent of the countywide average (as illustrated on Figure 2).
Such a project would not require further VMT analysis, provided the proposed development is similar in scale to existing employment uses.
If VMT generated by a project is not presumed to be less than significant based on the screening maps, it does not necessarily mean that the project would have a significant VMT impact, only that a less than significant VMT impact finding cannot be assumed without further analysis to make that determination.
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Small Projects
Small projects that are forecasted to generate fewer than 110 daily motor vehicle trips are generally considered to have a less than significant VMT impact, consistent with OPR Guidelines. Small projects meeting this screening criteria based on a trip generation forecast would not require further VMT analysis.
Transit-Oriented Development
Certain projects within one-half (0.5) mile of a transit stop at the intersection of two transit routes with 20 minute or less headways may be presumed to have a less than significant impact on VMT unless the project has a Floor Area Ratio (FAR) of less than 0.75, reduces the supply of affordable housing, or proposes to provide substantially more parking than required under the zoning code.
Transportation Projects
Types of transportation projects that are unlikely to lead to a measurable or substantial increase in vehicle travel may be presumed to have a less than significant VMT impact. Such projects generally include:
• Transit and Active Transportation Projects (e.g. sidewalk gap closure, increased transit frequency, bike lane striping)
• Roadway Projects which decrease automobile capacity and/or increase priority of non-automobile modes such as transit, pedestrian, and bicycle travel
Vehicle Miles Traveled (VMT)
VMT refers to the amount and distance of automobile travel “attributable to a project.” VMT Citywide Average
Citywide VMT is the average number of miles traveled by residents and employees of Calistoga per day.
VMT Countywide Average
Countywide VMT is the average number of miles traveled by residents and employees of Napa County per day.
Vehicle Miles Traveled per Capita
VMT per capita applies to residential projects and is the proposed project’s VMT divided by the number of residents the project can house. Residential projects include, but are not limited to single-family residences, multifamily residences, and mobile homes.
Vehicle Miles Traveled per Employee
VMT per employee applies to work projects and is the project’s VMT divided by the number of employees that would serve the project. Work projects include, but are not limited to, office, office parks, light industrial, warehousing, manufacturing, and business parks.
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Attachment 2: Methodology
The following data, as shown in Table 2, are provided by the Napa Valley Transportation Authority (NVTA) and TJKM.
Table 2. Napa County VMT Rates (Residential & Employment) Jurisdiction VMT per Capita (Residential) VMT per Employee American Canyon 17.00 31.37
Calistoga 9.82 16.96
Napa City 11.33 25.15
St Helena 9.16 17.41
Yountville 15.98 13.34
Napa Unincorporated 23.50 17.97
Highway 29 Corridor PDA 15.83 22.22
American Canyon PPA 16.91 19.99
Napa County Average 14.18 22.00
Recommended Impact Threshold
(85% of County average) 12.05 18.70
Source: NVTA Model & TJKM (2021).
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Attachment 3: NVTA Background on VMT Rate Calculations
Napa Valley Transportation Authority (NVTA) collaborates with the Solano Transportation Authority (STA) to update and maintain the Solano Napa Activity-Based Model (SNABM). This model is used to calculate and predict travel patterns in the region.
The SNABM determines the VMT Rates of Traffic Analysis Zones (TAZ) as shown in Figures 1 and 2.
Traffic Analysis Zones in Napa County are smaller areas that are split near major transit stops and demographic data to more accurately measure existing and future travel patterns.
As shown in Table 2, the VMT Rates per Capita and VMT Rates per Employee for the City of Calistoga are noticeably lower than the Countywide average and Recommended Impact Threshold.
The California Office of Planning and Research (OPR) states the following:
• Proposed residential projects exceeding a level of 15 percent below existing VMT per capita may indicate a significant transportation impact.
• Proposed projects with employment use exceeding a level of 15 percent below existing VMT per employee may indicate a significant transportation impact.
15 percent below existing VMT is equivalent to 85% of the existing Napa County average.
The Recommended Impact Thresholds are achieved by taking 85% of the existing Napa County average:
14.18 VMT per Capita x 0.85 = 12.05 VMT per Capita
22.00 VMT per Employee x 0.85 = 18.70 VMT per Employee
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This memorandum describes recommended vehicle miles traveled (VMT) impact thresholds and screening criteria for consideration by the City of Calistoga, on behalf of the Napa Valley Transportation Authority (NVTA). These recommendations are based on current California Environmental Quality Act (CEQA) requirements pertaining to vehicle miles traveled (VMT) and Senate Bill (SB) 743.
1. BACKGROUND
CEQA, enacted in 1970, requires state and local agencies to inform decision makers and the public about the potential environmental impacts of proposed projects, and to reduce those impacts to the extent feasible. The California Office of Planning and Research (OPR) develops the CEQA Guidelines to interpret CEQA statute and published court decisions.
The version of the CEQA Guidelines adopted on December 28, 2018, includes updates related to analyzing transportation impacts pursuant to SB 743 that are contained in section 15064.3 (b). SB 743 changed the way that public agencies evaluate the transportation impacts of projects under CEQA, recognizing that roadway congestion, while an inconvenience to drivers, is not itself an environmental impact (see Public Resource Code, Section 21099, subd. (b)(2)). Therefore, traffic level of service (LOS) may no longer be used to evaluate potential transportation impacts under CEQA.
OPR identified VMT as the most appropriate metric to determine the significance of transportation impacts in a manner that promotes the reduction of greenhouse gas emissions, the development of multimodal transportation networks, and a diversity of land uses (OPR 2018). The new requirements, as described in CEQA Guidelines section 15064.3 (b), include the following specifications:
• “Vehicle miles traveled” refers to the amount and distance of automobile travel “attributable to a project1
.” Other relevant considerations may include the effects of the project on transit or non- motorized travel.
1 As described separately in the Technical Advisory on Evaluating Transportation Impacts in CEQA (OPR, December 2018), VMT re-routed from other origins or destinations as the result of a project would not be attributable to a project except to the extent that the re-routing results in a net increase in VMT. For example, OPR guidelines note that retail projects typically re- route travel from other retail destinations, and therefore a retail project may lead to increases or decreases in VMT, depending on previously existing travel patterns. Similarly, a large share of retail trips are “pass-by trips” that would not generate VMT attributable to a retail project.
TECHNICAL MEMORANDUM
Date: August 5, 2021
To: NVTA and City of Calistoga Project No.: 069-026 Napa County VMT From: Colin Burgett, Vamsee Modugula and Arthur
Chen
Jurisdiction: City of Calistoga
Subject: VMT Recommendations for City of Calistoga
Attachment 4: TJKM Reccomendations Item #8.4.
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• Lead agencies have discretion to choose the most appropriate methodology to evaluate a project’s vehicles miles traveled, including whether to express the change in absolute terms, per capita, per household or any other measure.
• A lead agency may use models to estimate a project’s VMT and may revise those estimates to reflect professional judgment based on substantial evidence. If existing models or methods are not available to estimate the VMT for the project being considered: a lead agency may evaluate the project’s VMT qualitatively.
2. CEQA SIGNIFICANCE CRITERIA FOR TRANSPORTATION IMPACTS Pursuant to the CEQA Guidelines (as amended effective July 1, 2020), potentially significant environmental impacts related to transportation would result if a project would:
1. Conflict with a program plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle, and pedestrian facilities; or
2. Conflict or be inconsistent with CEQA Guidelines section 15064.3 (b), which pertains to vehicle miles traveled (VMT); or
3. Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible use (e.g., farm equipment); or
4. Result in inadequate emergency access
Relevant to criterion 1 above: to make a less than significant determination, projects will need to be found consistent with relevant adopted transportation plans, ordinances or policies, including those contained within the Calistoga General Plan and other relevant plans such as the Countywide Transportation Plan, Napa Countywide Bicycle Plan, Napa Countywide Pedestrian Plan, Napa County Short Range Transit Plan, and the Metropolitan Transportation Commission’s Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS). However, if a project results in traffic delay that conflicts with an adopted level of service (LOS) standard or policy (including the LOS policy described in on page CIR-2 of the Calistoga General Plan Circulation Element): such a conflict shall not be considered a significant environmental impact under CEQA (based on the current CEQA guidelines). Instead, any analysis of LOS (if still desired as part of the development review process) could be required for planning and informational purposes during project review (but not for the purpose of evaluating environmental impacts under CEQA).
Relevant to criterion 2 above: the remainder of this report describes the recommended VMT Impact Analysis process, criteria, and impact thresholds for consideration by the City of Calistoga, to satisfy the requirements of CEQA Guidelines section 15064.3 (b).
3. STATEWIDE RECOMMENDATIONS FOR ASSESSING VMT
In December 2018, OPR circulated its most recent Technical Advisory on Evaluating Transportation Impacts in CEQA that provides recommendations and describes various options for assessing VMT for transportation analysis purposes. The VMT analysis options described by OPR are primarily tailored towards single-use residential, office or retail projects. OPR recommends the following methodology and criteria for specific land uses:
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• For residential projects, OPR recommends that VMT impacts be considered potentially significant if a residential project is expected to generate VMT per Capita (i.e., VMT per resident) at a rate that exceeds 85 percent of a regional or citywide average. Based on this OPR guidance:
this report recommends that the VMT impact threshold for residential projects in Calistoga should be 85 percent of the Napa County average rate for VMT per Capita. • For office projects, OPR recommends that VMT impacts be considered potentially significant if an office project is expected to generate VMT per Employee at a rate that exceeds 85 percent of a regional average. This approach may also be applicable to other land use types in which in most trips are made by employees (not customers). Based on this OPR guidance: this report recommends that the VMT impact threshold for projects in Calistoga in which most trips would be generated by employees (not customers) should be 85 percent of the Napa County average rate for VMT per Employee.
• For retail projects, OPR recommends that VMT impacts be considered potentially significant if a project results in a net increase in total VMT. This approach considers the likelihood that retail developments may lead to increases or decreases in VMT, depending on previously existing retail travel patterns. This approach may also be used for other types of projects with customer components. Based on this OPR guidance: this report recommends that VMT impacts for retail and other customer-serving uses should be based on whether VMT attributable to customers will result in a significant net increase in VMT.
• OPR does not provide specific guidance on evaluating other land use types, such as hotels, except to say that other land uses could choose to use the method applicable to the land use with the most similarity to the proposed project.
• For mixed-use projects, OPR describes several options that include (1) evaluating each land use separately; or (2) evaluating mixed-use projects based on the method applicable to the dominant land use. Evaluating each land use separately would potentially fail to measure the positive effects of mixed-use projects in reducing VMT.
OPR also recommends exempting some project types from VMT analysis based on the likelihood that such projects will generate low rates of VMT. OPR recommends that projects generating less than 110 motor vehicle trips per day generally may be assumed to cause a less than significant transportation impact.
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4. VMT RATES IN CALISTOGA & NAPA COUNTY
The current rates of VMT per Capita and VMT per Employee in Napa County, are shown on Table 1, including the recommended impact thresholds for Calistoga that would be based on 85 percent of the countywide rate). As shown: the rates of VMT per resident, and per job, for land uses in Calistoga are well below the Countywide averages, and below the proposed impact thresholds.
Table 1: Napa County VMT Rates (Residential & Employment) Jurisdiction VMT per Capita
(Residential)
VMT per
Employee
American Canyon 17.00 31.37
Calistoga 9.82 16.96
Napa City 11.33 25.15
St Helena 9.16 17.41
Yountville 15.98 13.34
Napa Unincorporated 23.50 17.97
Highway 29 Corridor PDA 15.83 22.22
American Canyon PPA 16.91 19.99
Napa Country Average 14.18 22.00
Recommended Impact Threshold
(85% of County average) 12.05 18.70
Source: NVTA Model & TJKM (2021).
5. RECOMMENDED VMT SCREENING CRITERIA
This section describes recommended VMT screening criteria for potential adoption by the City of Calistoga. VMT impacts may be presumed to be less than significant if a project meets screening criteria, consistent with OPR guidance summarized on Table 2. The screening criteria can be based on project size, land use and/or locational characteristics. If a project does not meet any of the screening criteria, then a detailed assessment of VMT attributable to a project would be required.
VMT for mixed-use projects VMT can be considered for each use separately or evaluated for the project’s dominant use, taking credit for internal capture. If the mixed-use project is composed entirely of any of the abovementioned low-VMT project types, then the project would be considered to have a less than significant impact on VMT.
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Table 2: VMT Screening Criteria
Type of
Project
OPR Recommended Screening Criteria Recommended Screening Criteria for City of Calistoga
Small Projects Projects that generate fewer than 110 motor vehicle trips per day
Same as OPR recommendation
Residential
Uses in LowVMT Areas
Residential projects located in low-VMT areas that
do not exceed 85% of a regional or citywide average
for VMT per Capita (i.e., VMT per Resident)
Same as OPR recommendation (with
threshold to be based on 85% of the
countywide average)
Employment
Uses in LowVMT Areas
Office projects located in low-VMT areas that do not
exceed 85% of a regional average for VMT per
Employee2
Same as OPR recommendation (with
threshold to be based on 85% of the
countywide average). In addition to
office developments: this threshold
would be applied to commercial
projects in which most daily trips
would be generated by employees (not
customers)
Local-serving
Retail
Retail projects of 50,000 sq. ft. or less. Same as OPR recommendation Hotel Projects
in Low-VMT
Areas
N/A3 Hotels projects in areas where the rate
of VMT per Employee does not exceed
85 percent of the Countywide average,
provided that VMT attributable to
hotel guests is not anticipated to result
in a significant increase in total VMT.
Affordable
Housing
100% affordable housing projects in infill locations. Same as OPR recommendation Projects in
Proximity to
Major Transit
Stops
Projects that are located within a half mile of an
existing or planned high-quality transit corridor4 or
major transit station, and: (1) is high density
(minimum floor area ratio of 0.75), (2) does not
exceed parking requirements, (3) is consistent with
Plan Bay Area, and (4) does not replace affordable
units with smaller numbers of moderate- or above
moderate- income units.
Projects within one-half (0.5) mile of a
transit stop with 15 minute or less
headways , unless the project has a
Floor Area Ratio (FAR) of less than
0.75, reduces the supply of affordable
housing, or includes more parking than
required under the zoning code.
Transportation
Projects
Roadway, transit, bicycle, and pedestrian projects
that do not lead to a measurable increase in vehicle
travel.
Same as OPR recommendation
Source: OPR Technical Advisory on Evaluating Transportation Impacts in CEQA, December 2018, and TJKM, 2021. 2 OPR recommendations are limited to residential, office and retail uses, and transportation projects. 3 OPR did not provide recommendations for assessing hotel VMT. The recommended methodology described in this report would assess VMT attributable to hotel employees based on the rate of VMT per Employee (similar to office uses) and would assess VMT attributable to hotel guests based on the effect of guest VMT on total VMT (similar to retail uses). Hotels typically re- route guest VMT from other lodging options, and therefore a hotel project may lead to increases or decreases in VMT attributable to hotel guests. 4 High Quality Transit Corridor is defined as a corridor with fixed route bus service with service intervals no longer than 15 minutes duringpeak commute hours per Public Resources Code Section 21155.
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Small Projects
Small projects that are forecasted to generate fewer than 110 daily motor vehicle trips are generally considered to have a less than significant VMT impact, consistent with OPR Guidelines. Small projects meeting this screening criteria based on a trip generation forecast would not require further VMT analysis.
Residential & Employment Uses in Low-VMT Areas
Based on OPR guidance, residential or employment-oriented projects in low-VMT areas may be presumed to have less than significant VMT impacts and would not require further VMT analysis. The NVTA screening map tool shows low-VMT areas where residential or workplace VMT does not exceed 85 percent of the Countywide average:
• Residential Uses: Residential projects proposed for sites within the boundaries of areas with average rates of VMT per Capita that do not exceed 85 percent of the countywide average, as illustrated on Figure 1, can be assumed to have a less than significant VMT impact. Such projects would not require further VMT analysis, provided the proposed residential development provides similar multi-modal access provisions as existing residential development in the area.
• Employment Uses: Commercial projects where most daily trips would be generated by on-site employees (not customers), such as proposed office developments, can be presumed to have a less than significant VMT impact and would not require further VMT analysis if proposed for sites within areas with average VMT per Employee that does not exceed 85 percent of the countywide average (as illustrated on Figure 2). Such a project would not require further VMT analysis, provided the proposed development is similar in scale to existing employment uses.
If VMT generated by a project is not presumed to be less than significant based on the screening maps, it does not necessarily mean that the project would have a significant VMT impact, only that a less than significant VMT impact finding cannot be assumed without further analysis to make that determination.
Local-serving Retail Projects
Retail projects that are less than 50,000 square feet may be presumed to have a less than significant, VMT impact if the retail is locally serving (including retail projects that would serve local hotel guests).
This is based on the OPR recommendations that VMT impacts associated with customer-serving uses should be based on whether the project results in a net increase in total VMT. OPR guidelines note that retail projects typically re- route travel from other retail destinations, and therefore a retail project may lead to increases or decreases in VMT, depending on previously existing travel patterns. Similarly, a large share of retail trips are “pass-by trips” that would not generate VMT attributable to a retail project.
Hotel Projects in Low-VMT Areas
Hotels projects in areas where the rate of VMT per Employee does not exceed 85 percent of the Countywide average (based on the NVTA screening tool as shown on Figure 2) may be presumed to have Item #8.4.
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a less than significant VMT impact, provided that VMT attributable to hotel guests is not anticipated to result in a significant increase in total VMT.
Affordable Housing Projects
Affordable housing in infill locations generally improves jobs-housing balance, shortening commutes and reducing VMT. Given the relatively low citywide rate for residential VMT in Calistoga (which is well below the countywide average) and proximity to employment in the hospitality industry: it is recommended that 100 percent affordable housing projects in infill locations be presumed to have a less than significant VMT impact, consistent with OPR guidance.
Transit-Oriented Development
Certain projects within one-half (0.5) mile of a transit stop at the intersection of two transit routes with 15 minute or less headways may be presumed to have a less than significant impact on VMT unless the project has a Floor Area Ratio (FAR) of less than 0.75, reduces the supply of affordable housing, or proposes to provide more parking than required under the zoning code.
Transportation Projects
Types of transportation projects that are unlikely to lead to a measurable or substantial increase in vehicle travel may be presumed to cause a less than significant VMT impact. Such projects generally include:
• Transit and Active Transportation Projects
• Roadway Projects which decrease automobile capacity and/or increase priority of nonautomobile modes such as transit, pedestrian, and bicycle travel Item #8.4.
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Figure 1 – Screening Map for Residential Uses (VMT per Capita)- Calistoga Item #8.4.
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Figure 2 – Screening Map for Employment Uses (VMT per Employee)- Calistoga Item #8.4.
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6. THRESHOLDS OF SIGNIFICANCE FOR VMT IMPACTS
When a project does not meet one of the screening criteria identified in the previous section, then a detailed VMT assessment would be required for projects subject to CEQA, to quantify the relevant VMT attributable to the project, provide findings of significance, and identify potential VMT mitigations where applicable.
The recommended significance thresholds, incorporating guidance described in the previous sections, are summarized on Table 3 below.
Table 3: Recommended VMT Impact Thresholds for City of Calistoga Type of Project Threshold Calculation Daily VMT Threshold Residential 85% of Countywide average rate of
VMT per Capita (i.e., VMT per
Resident).
12.05 VMT per Resident
Office & Other Employment Uses
(defined as uses in which most
daily trips would be generated by
employees)
85% of Countywide average rate of
VMT per Employee
18.70 VMT per Employee
Retail & Other Customer-serving
Uses (defined as uses in which
most daily trips would be
generated by customers)
Net change in total VMT. Net increase in total VMT would be considered potentially significant
(excluding employee VMT if the
rate of VMT per Employee is below
the threshold of 18.7 VMT per
Employee).
Hotel VMT attribute to hotel employees:
85% of Countywide average rate of
VMT per Employee.
VMT attributable to hotel guests:
net change in total VMT.
18.70 VMT per Employee
Net increase in total VMT
attributable to hotel guests would
be considered potentially
significant.
Transportation Projects Net change in total VMT. Net increase in total VMT would be considered potentially significant.
Source: TJKM, 2021.
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