Highway Intersection Safety

In Highway Intersection Safety, you'll learn ...

• The kinematic principles involved in calculating needed sight distance at intersections
• Past and current AASHTO policies adopted for intersection design
• Tools to address contributing factors and measures to enhance safety using a range of treatments at intersections
• Forensic analysis of an intersection accident where sight distance was an important issue

Overview

Preview a portion of this course before purchasing it.

Credit: 1 PDH

Length: 24 pages

This course will help highway engineers, traffic engineers, and engineers involved in the maintenance and public works to design and operate at-grade intersections with greater safety. It will also assist forensic engineers in the investigation and analysis of intersection accidents and offering opinions on liability. Technical requirements for Traffic Control Devices and sight distance are covered, along with measures to address safety problems at existing intersections.

At-grade intersections are a major source of traffic conflict and require more attention and judgment from motorists than any other highway feature. Entering or crossing a highway from an intersection requires difficult assessments of the speed, time, and distance to approaching vehicles. It also calls into play the capability (acceleration) of one’s own vehicle. Many motorists are very poor judges of these important measures.

The major parameters affecting safety at intersections are geometric design, speed, sight distance, signing, and signalization. Geometric design is well covered in readily available publications such as A Policy on Geometric Design of Highways and Streets (AASHTO) and is not the subject of this course. Signalization is addressed only as a possible safety measure.

To be safe, every intersection must provide adequate sight distance for turning, crossing, and entering motorists. The kinematic principles involved in calculating needed sight distance are provided, along with past and current AASHTO policies adopted for intersection design. The kinematic principles are then demonstrated in forensic analysis of an intersection accident where sight distance was an important issue.

Safely operating an intersection also requires the proper selection and use of traffic control devices, as well as an understanding of their limitations. Appropriate warning signs need to be utilized and then suitably located to ensure adequate visibility. This course will direct the student to appropriate signs called for under the Manual on Uniform Traffic Control Devices and also address their effectiveness. For new intersections and those experiencing accident problems, this course provides tools to address contributing factors and measures to enhance safety using a range of treatments.

Specific Knowledge or Skill Obtained

This course teaches the following specific knowledge and skills:

• The primary elements affecting safety at highway intersections
• Principles of kinematics to determine sight distance needed for various movements into an intersection and for accident investigations
• Current AASHTO Policy regarding intersection sight distance and application of the Gap Acceptance model
• Comparison between results from the kinematic and gap acceptance models applied to sample conditions
• The types and applications and location requirements for both regulatory and warning signs under the MUTCD
• Taking into account maintenance in the selection operation of traffic signs
• The range of safety improvement measures that can be taken, their limitations, and effectiveness
• The factors contributing to a real-world fatal intersection accident and how these principles are applied

Certificate of Completion

You will be able to immediately print a certificate of completion after passing a multiple-choice quiz consisting of 12 questions. PDH credits are not awarded until the course is completed and quiz is passed.