Preface

Non-discrimination

Texas Department of Transportation (TxDOT) policy is to ensure that no person will on the grounds of race, color, national origin, sex, age or disability be excluded from the participation in, be denied the benefits of, or otherwise be subjected to discrimination under any of our programs or activities.

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Overview

TxDOT developed the Roadway Design Manual to provide guidance in the geometric design of roadway facilities. This manual contains geometric design recommendations and not absolute design requirements.

The Roadway Design Manual represents a synthesis of current information and operating practices related to the geometric design of roadway facilities. The presentation of updated design values does not imply that existing facilities are unsafe or mandate improvement projects. Infrastructure projects are by their nature long-lived facilities. While design methodologies are constantly being improved, the implementation of these improvements typically occurs as projects are built, or rebuilt, in future undertakings.

Traditional roadway project development is expanding to include consideration of the impact on non-facility users and the environment. This more complex approach must take into account both the individual project priorities and the relative priorities of the entire roadway system. Therefore, effective design needs to provide not only beneficial design components, but also the most beneficial total roadway system.

While much of the material in the Roadway Design Manual can be considered universal in most geometric design applications, many areas are subjective and may need varying degrees of modification to fit local project conditions. The decision to use specific design guidance at a particular location should be based on an engineering study of the location, operational experience, and objective analysis. Thus, while this document provides guidance for the geometric design of highways and streets, it is not a substitute for engineering judgment. Further, while it is the intent that this document provide geometric design guidance, the Roadway Design Manual does not represent a legal requirement for roadway design.

Roadway design is a continually evolving process. As additional information becomes available through experience, research, and/or in-service evaluation, this guide will be updated to reflect current state-of-the-practice geometric design guidance for roadway facilities.