Signalized Intersections Part III – Treatments

Vincent D. Reynolds, MBA, P.E.

Course Outline

The basic function of signalized intersections is to sequence right-of-way between intersecting streams of users. Research has shown that, under the right circumstances, the installation of traffic signals will reduce the number and severity of crashes.

This 9 hour course is the third part of a three part series and will introduce to the reader to the treatments that can be applied to mitigate a known safety or operational deficiency.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of course materials.

Learning Objective

At the conclusion of this course, the student would have learned the following:

• Pedestrian treatments;
• Bicycle treatments;
• Transit treatments;
• Traffic control treatments;
• Illumination;
• Signal coordination;
• Access Management;
• Grade separation treatments;
• Intersection reconfiguration treatments;
• Signing and speed control treatments;
• Sight distance treatments;
• Left-turn movement treatments;
• variable lane use treatments;
• The key features of median design;
• When flush medians should be used at intersections;
• The preferred width of bullet-nose medians;
• How wider medians effect multiple vehicle crash rates;
• Max. height of plants at signalized intersections;
• Ideal location of driveways with full access;
• The relative crash rate for unsignalized intersections with access points;
• Types of emergency signal vehicle detection technology available;
• Common methods of reducing pedestrian crossing distances;
• How the curb radius affects the speed of vehicles along the roadway;
• When curb extensions are needed along the roadway;
• How pre-times protected pedestrian phases reduce pedestrian collisions;
• When an exclusive pedestrian phase would be needed;
• The benefits and liabilities of pedestrian tunnels or pedestrian overpasses;
• How intersection size can effect the loss time;
• How commercial vehicles are effected by intersection angles;
• When converting some four-leg intersections to two T-intersections are advantageous to traffic movement;
• Potential roadblocks to continuous flow intersections;
• The characteristics of an compressed diamond;
• The advantages of using a mast arm or span wire;
• The potential benefits related to advance warning treatments;
• The advantages of using rumble strips; and
• How larger signs can decrease collisions.
  

Intended Audience and Benefit

This is intended for planners, traffic engineers, highway engineers, designers, operation analysts, project managers, or any persons working in civil engineering field or anyone with an interest in signalized intersections.

Course Introduction

Intersections occur along roadways in order to connect intersecting streams of traffic. Several conflicts can occur at intersections which involve pedestrians, vehicles, and bicycles. These conflicts can be classified as merging, diverging and crossing. The basic function of signalized intersections is to sequence right-of-way between intersecting streams of users. Research has shown that, under the right circumstances, the installation of traffic signals will reduce the number and severity of crashes.

Course Content

This course will introduce to the reader to the treatments that can be applied to mitigate a known safety or operational deficiency. Chapters 8-12 are the sections that are required to be read in order to complete the quiz for this Part of the series; the remaining chapters are covered in Parts I and II of this course.

Signalized Intersections Part III – Treatments

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Course Summary

The information presented in this course provided a detailed overview of the design and operation of signalized intersections.
 
Using good engineering judgment is always paramount in any situation. Utilizing good judgment and the knowledge gained in this course will aid the reader with the knowledge to successfully design safe and efficient signalized intersections.

Related Links

For additional technical information related to this subject, please visit the following websites:

http://www.fhwa.dot.gov/
www.aashto.com
www.ite.com

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

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DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.

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