Highway Traffic Barriers – Testing, Performance, and Design

In Highway Traffic Barriers – Testing, Performance, and Design, you'll learn ...

• The five (5) major types of Guide Rail
• How current barrier designs have evolved to meet the changing fleet of vehicles traversing the roads
• Why roadside barriers are not tested and designed for speeds up to 70 MPH
• How to calculate the parameters of impact severity, critical speed, and maximum impact angle

Overview

Preview a portion of this course before purchasing it.

Credit: 2 PDH

Length: 29 pages

This course will assist highway engineers, safety experts, forensic engineers, public works officials, and other professionals in their understanding of the principals involved in the testing, design, and performance of roadside highway barriers. The course shows how current designs have evolved to meet the changing fleet of vehicles traversing the roads.

The five (5) major types of Guide Rail are described in the course, along with their limitations and suitability for various site conditions and types of road. Explanations of how these types of rails performed in full-scale crash testing and in actual service are included. Problems experienced with previously approved designs are covered to assist the engineer in determining the necessity of replacing existing installations.

Historical testing criteria are described, including the concept of test level as a performance measure. The standard values used for design speed and impact angle are explored, along with theories behind their adoption. The course addresses the question of why roadside barriers are not tested and designed for speeds up to 70 MPH, which are often posted on modern freeways.

The history of roadside barriers is included to show how various designs evolved in response to problems experienced in real-world crashes. Many earlier designs performed as originally intended, but are no longer acceptable due to changes in the fleet of vehicles on the road. The most significant changes resulted from the popularity of SUVs and also recognition of the need to handle greater numbers of vans and pickup trucks on the road.

Using examples of two very serious accidents, the course demonstrates how crashes can differ from theoretical designs and standard testing conditions. Applying principles of kinetic energy, the concept of impact severity (I.S.) is explained as a means of comparing crashes at different speeds and impact angles. The course will teach you how to calculate the parameters of I.S., critical speed, and maximum impact angle.

Specific Knowledge or Skill Obtained

This course teaches the following specific knowledge and skills:

• The history of barrier development and how the current designs have evolved and were modified to meet changing standards
• Current and prior standards for the testing of roadside barriers and how various designs have performed under criteria contained in MASH, NCHRP 350 and NCHRP230
• The major types of roadside barriers that are currently acceptable and their general suitability for various classes of road
• Performance limitations of currently approved roadside barriers and of earlier guide rail designs that remain in place today
• Important parameters for evaluating real-world crashes including speed estimates for yawing vehicles using Critical Speed analysis
• Calculations needed to investigate barrier accidents by determining Impact
• Severity, minimum turning radius and maximum impact angle
• Recognize how many real-world crashes differ from certain assumptions made during standard testing and design
• Understand the factors that contributed to barrier penetration in examples given of two fatal accidents
• How the parameters covered in the course can be applied to real-world crash investigations

Certificate of Completion

You will be able to immediately print a certificate of completion after passing a multiple-choice quiz consisting of 20 questions. PDH credits are not awarded until the course is completed and quiz is passed.