• ♦Manual Notice 2015-1
• ►1. Introduction
  • ►1. Overview
    • ♦Purpose of Manual
    • ♦Users of Manual
    • ♦Responsibilities
  • ►2. Background
    • ♦Basic Speed Law
    • ♦Prima Facie Concept
    • ♦Authority to Set Speed Zones
    • ♦Higher Maximum Speed Limit
    • ♦Local Authority and TxDOT
    • ♦Value of Speed Zoning
    • ♦Guidelines for Selecting Speed Limits
  • ►3. Factors Affecting Safe Speed
    • ♦Introduction
    • ♦Design and Physical Factors of the Roadway
    • ♦The Vehicle
    • ♦The Driver
    • ♦Traffic
    • ♦Weather and Visibility
    • ♦Accident Reconstruction Speed Limits
• ►2. Regulatory and Advisory Speeds
  • ►1. Application of Regulatory and Advisory Speeds
    • ♦Introduction
    • ♦Regulatory Speeds
    • ♦Advisory Speeds
    • ♦Advisory Speed Sections in Regulatory Zones
    • ♦Regulatory Versus Advisory Speeds
  • ►2. Regulatory Speed Zones
    • ♦Introduction
    • ♦Within Incorporated Cities or Towns
    • ♦Highway Approaches to Incorporated Municipalities
    • ♦Minimum Speed Limits
    • ♦Regulatory Speed Signs (R2 Series)
    • ♦Signs Within Cities and Towns
  • ►3. Construction Regulatory and Advisory Speeds
    • ♦Introduction
    • ♦Advisory Construction Speeds
    • ♦Regulatory Construction Speed Zones
    • ♦Request for Regulatory Construction Speed Zones
    • ♦Advisory Speed Construction Warning Plates (CW13-1)
    • ♦Regulatory Construction Speed Limit Signs
    • ♦Covering or Removing Temporarily Unnecessary Reduced Speed Signs
    • ♦Signs Installed by the Contractor
  • ►4. School Speed Zones
    • ♦Introduction
    • ♦Planning
    • ♦Prompt Installation Important
    • ♦Signs
    • ♦Intervals of Operation
    • ♦More Information
  • ►5. Private Road Speed Zones
    • ♦Introduction
    • ♦Eligibility Requirements
    • ♦Process Initiation
    • ♦Procedure
• ►3. Speed Zone Studies
  • ►1. Overview
    • ♦Engineering and Traffic Investigation
    • ♦Interim Speed Limits for New or Reconstructed Highways
    • ♦Scope of Study
  • ►2. Determining the 85th Percentile Speed
    • ♦General Concepts
    • ♦Theory
    • ♦Statistical Rationale
    • ♦Speed Checks for Existing Highways
    • ♦Speed Checks for New or Reconstructed Highways
    • ♦Operation of Speed Check Stations
    • ♦Location of Speed Check Stations
    • ♦Measuring Speeds
    • ♦Recording Measured Speeds
    • ♦Calculating 85th Percentile Speed
    • ♦Recording the Information
    • ♦Incomplete Data
  • ►3. Developing Strip Maps
    • ♦Strip Map Blanks
    • ♦Scale for Strip Map
    • ♦Field Entry Data
    • ♦City Limits
    • ♦Schools
    • ♦Showing Crashes on Strip Maps
  • ►4. Speed Zone Design
    • ♦Zone Length
    • ♦Transitions
    • ♦Urban Areas
    • ♦Directional Differences
    • ♦Variation from 85th Percentile
    • ♦Blanket Lowering of Maximum Speed Limits
    • ♦Trial Runs
    • ♦Location of Regulatory Speed Limit Signs
  • ►5. Rechecks of Speed Zones
    • ♦Introduction
    • ♦Frequency of Rechecks
    • ♦Procedure
  • ►6. Environmental Speed Limits
    • ♦Introduction
    • ♦Existing Environmental Speed Limits
    • ♦New Environmental Speed Limits Prohibited
• ►4. Speed Zone Approval
  • ►1. Overview
    • ♦Introduction
    • ♦Regional Mobility Authorities and Regional Tollway Authorities
  • ►2. Approval Process
    • ♦Outside an Incorporated City
    • ♦Within an Incorporated City
    • ♦Adjacent Portions Within and Outside an Incorporated City
    • ♦Speed Zones Unacceptable to a City
    • ♦Filing of Strip Maps
    • ♦Transportation Commission Minute Order
• ▼5. Application of Advisory Speeds
  • ►1. Overview
    • ♦Introduction
    • ♦Advisory Speed Sign Posting
  • ►2. Curves and Turns
    • ♦Introduction
    • ♦Objective
    • ♦Methods to Establish Curve Warning Advisory Speeds
    • ♦Direct Method
    • ♦GPS Method
    • ♦Design Method
    • ♦Ball-Bank Method
    • ♦Calculated Speed
    • ♦Selection of Car and Mounting of Bank Indicator
    • ♦Before Conducting Test Runs
    • ♦Calibrating Speedometer
    • ♦Zeroing the Bank Indicator
    • ♦Conducting Bank Indicator Test Runs
    • ♦Alternate Ball-Bank Indicator Test Run Method
    • ♦Selecting Speed for Posting
  • ▼3. Intersections
    • ♦Introduction
    • ♦View Obstructions
  • ►4. Narrow and One-Lane Bridges
    • ♦Introduction
    • ♦Placement of Signs
  • ►5. Descending Grades of Six Percent or Greater
    • ♦Introduction
    • ♦Determining Minimum Sight Distances
    • ♦Calculation
    • ♦If a Curve is Involved
  • ►6. Dips, Bumps, and Exit Ramps
    • ♦Dips and Bumps
    • ♦Exit Ramps
• ►A. Forms
• ♦B. Glossary

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Section 3: Intersections

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Introduction

Advisory zones may be posted at intersections such as traffic circles designed for an operating speed less than the speed of the approaches, and intersections with restricted sight distances that require a reduction in speed for safe operation.

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View Obstructions

For intersections having view obstructions, trial runs should be conducted to determine the safe and reasonable speed for the area. This speed may be posted as an advisory speed below a warning sign to warn motorists of the limited sight distance.