Why are Traffic Impact Studies required?

When planning a new development, whether residential, commercial, or mixed-use, local agencies often require a Traffic Impact Study (TIS), also known as a Traffic Impact Analysis (TIA), to evaluate how the proposed project will affect the surrounding roadway network. A TIS/TIA is a critical step in the land development process, especially in urbanized counties and cities, where development-related traffic impacts must be carefully reviewed and managed.

What Is a TIS/TIA?

A TIS/TIA is an engineering evaluation that assesses the potential traffic and transportation impacts of a proposed development. The goal of these studies is to ensure that new projects do not create undue congestion, compromise safety, or result in traffic conditions that exceed the capacity of nearby roads and intersections.

Types of TIS/TIA?

There are two main types of traffic studies used for this purpose:

1. Trip Generation Memorandum

   A Trip Generation Memorandum is a brief report generally used for small to medium-sized developments. It estimates the number and distribution of vehicle or person trips the project would generate based on its land use type and size.

2. Traffic Impact Study (TIS) / Traffic Impact Analysis (TIA)

   A TIS/TIA is a more comprehensive study typically required for medium to large developments. In addition to the trip generation analysis, it evaluates how the added traffic will affect surrounding roadways and intersections, and it identifies potential improvements or mitigation measures needed to maintain safe and efficient traffic flow.

Why Are TIS/TIA Important?

A TIS/TIA documents and analyzes several items:

• Assess Operational Impacts: Determines how increased vehicle, pedestrian, or rideshare activity may affect traffic flow, intersection delay, and overall roadway Level of Service (LOS).

• Ensure Public Safety: Evaluates whether access points, turning movements, and internal site circulation are designed to minimize conflicts and reduce crash potential.

• Identify Mitigation Needs: Recommends improvements such as added turn lanes, new signals, updated signal timings, or driveway modifications to accommodate projected demand.

• Support Informed Decisions: Helps transportation agencies and local governments make data-driven decisions regarding development approvals and conditions of approval.

• Ensure Compliance: Verifies consistency with comprehensive plans, concurrency requirements, and local access management policies.

Need a Traffic Study for Your Development?

Whether you're working on a new site plan or preparing for a development application, our team can help you navigate the traffic study process from start to finish. We specialize in preparing traffic studies that meet local requirements while supporting timely approvals. Contact us today to request a proposal or learn more about our services.