Background of the Tahoe Regional Planning Agency Project Impact Assessment Guidelines for Transportation

Land Use and Transportation Planning in the Lake Tahoe Basin

The Lake Tahoe Basin's land use and transportation planning is governed by a Bi-State Compact between Nevada and California, ratified by Congress. Established in 1969 and revised in 1980, the Tahoe Regional Planning Compact created the Tahoe Regional Planning Agency (TRPA), the nation’s first interstate environmental planning agency.

Under Article I, Section (b) of the Compact, TRPA is required to:

Adopt environmental threshold carrying capacities—standards necessary to preserve the region’s scenic, recreational, educational, scientific, and natural values while ensuring public health and safety.
Develop and enforce a Regional Plan and ordinances to achieve and maintain these environmental capacities.

Environmental Thresholds

In compliance with the Compact, TRPA adopted environmental thresholds in 1982 to address nine key resource areas:

Air Quality
Fisheries
Noise
Recreation
Scenic Resources
Soil Conservation
Vegetation Preservation
Water Quality
Wildlife

Among these, an air quality standard for Vehicle Miles Traveled (VMT) was established to address nitrate deposition concerns. As motor vehicle emissions improved, nitrate deposition ceased to be a major factor in lake clarity issues. Recognizing this, in April 2021, TRPA replaced the nitrate deposition threshold with a new mobility-related standard under the category Transportation and Sustainable Communities (TSC1): to reduce annual daily average VMT per capita by 6.8%—from 12.48 (2018 baseline) to 11.63 by 2045.

TRPA Planning Milestones

1969: Bi-State Compact adopted
1980: Bi-State Compact revised
1982: Environmental thresholds established
1987: Regional Plan and Code of Ordinances adopted
2012: Regional Plan Update adopted
2021: VMT threshold revised

The Lake Tahoe Regional Plan

The Bi-State Compact mandates the adoption and enforcement of a Regional Plan and corresponding ordinances to maintain environmental thresholds. Initially adopted in 1987 and comprehensively updated in 2012, the Lake Tahoe Regional Plan provides a framework for sustainable development and conservation.

Goals and Policies

The Regional Plan applies basin-wide and must be followed for all development projects. The Regional Land Use Map dictates land use consistency, with a strong emphasis on protecting natural and cultural resources. Transportation studies must align with the plan’s requirements, and any inconsistencies may lead to project denial or necessitate a plan amendment.

A key strategy of the Regional Plan is environmental redevelopment in designated Centers, which include:

High-Density Tourist District
Regional Centers
Town Centers

These Centers promote compact, mixed-use development with well-integrated bicycle and pedestrian infrastructure. Incentives such as higher densities, taller buildings, and coverage transfers encourage sustainable growth in centralized areas, reducing reliance on car travel and enhancing walkability, biking, and transit use.

Regional Transportation Plan

As the region’s Metropolitan Planning Organization, TRPA updates the Regional Transportation Plan (RTP) every four years. The RTP, an integral part of the Regional Plan, outlines strategies for:

Expanding transit services
Enhancing trails and pedestrian networks
Implementing transportation technology solutions
Promoting sustainable communities

The RTP also includes a project list detailing transportation improvements planned through 2045.

Area and Community Plans

To further refine land use and transportation strategies at the local level, TRPA oversees Area and Community Plans. These plans translate Regional Plan policies into location-specific strategies but do not override Regional Plan requirements.

Adopted Area Plans with Transportation Chapters:

Meyers Area Plan
Placer County Tahoe Basin Area Plan
South Shore Area Plan
Tahoe Valley Area Plan
Tourist Core Area Plan
Washoe County Tahoe Area Plan

In some cases, area plans include project-level transportation analyses. If a project’s VMT impacts have been fully analyzed under an area plan, further VMT assessments may not be necessary.

Additionally, three older Community Plans remain in effect from the 1987 Regional Plan, each with transportation-related guidelines:

Bijou / Al Tahoe Community Plan
Round Hill Community Plan
South Y Industrial Tract Community Plan

Code of Ordinances

The TRPA Code of Ordinances enforces Regional Plan policies through legally binding standards. For VMT analyses, key chapters include:

Chapter 3: Environmental Documentation – Establishes environmental documentation procedures.
Chapter 65: Air Quality / Transportation – Defines VMT assessment and mitigation standards.

TRPA Environmental Review Process

TRPA’s environmental review process is governed by Article VII of the Bi-State Compact and Chapter 3 of the Code of Ordinances. Certain project types are exempt from environmental review, including:

Single-family home construction and minor additions
Changes in use generating less than 650 additional daily VMT
Transfers or conversions of development rights

Projects requiring review must complete an Initial Environmental Checklist (IEC) or an Environmental Assessment (EA) to determine if a full Environmental Impact Statement (EIS) is needed.

Transportation-Related IEC Questions:

Will the project generate 650 or more daily VMT?
Will it impact parking demand or modify existing parking facilities?
Will it substantially affect transportation systems, including highways, transit, bike lanes, or pedestrian facilities?
Will it alter existing circulation patterns for people or goods?
Will it affect waterborne, rail, or air traffic?
Will it increase traffic hazards for vehicles, bicycles, or pedestrians?

This document provides guidance only on Question 13.a (VMT impacts). For other transportation-related impacts, applicants should contact TRPA for further analysis procedures.

California Environmental Quality Act (CEQA)

California’s CEQA process is similar to TRPA’s review system and applies to discretionary actions by public agencies. VMT analysis is required under CEQA per Senate Bill 743 (SB 743, 2013), which replaced Level of Service (LOS) with VMT as the preferred metric for assessing transportation impacts.

TRPA’s VMT analysis aligns with SB 743 to avoid conflicting regulatory procedures. However, differences exist:

TRPA analyzes in-basin VMT only
CEQA requires analysis of full-trip length VMT

For projects in California, analysts should account for both TRPA and CEQA requirements.

Additional VMT Analysis Guidelines

Applicants may need to reference other VMT analysis guidelines, including:

Placer County Transportation Study Guidelines (2020)
El Dorado County Transportation Impact Study Guidelines (2014)
California OPR’s Technical Advisory on CEQA Transportation Impacts (2018)
Caltrans' VMT-Focused Transportation Impact Study Guide (2020)
Caltrans' Transportation Analysis Framework and CEQA Guidelines (2020)