Design Policy - Roadside Safety Design

WSDOT publishes roadside safety design, including design for traffic barriers, impact attenuators, and rumble strips. State roadside safety policies are covered in Division 16 of the Design Manual.

Major Topics
Frequently Asked Questions (docx 22 kb)
Cable Barriers
Beam Guardrail Terminals and Anchors
Impact Attenuators (docx 22 kb)
Rumble Strips
MASH Implementation (pdf 139 kb)
The Manual for Assessing Safety Hardware (MASH) updated the rules for crash testing roadside hardware. See what FHWA has to say about MASH implementation.

Design Manual
Chapter 1600, Roadside Safety (pdf 678 kb) addresses the area outside of the roadway and is an important component of total highway design. Guidance on roadside safety issues is presented in this chapter.
Chapter 1610, Traffic Barriers (pdf 1.2 mb) includes traffic barriers, terminals and transitions that are approved for use by WSDOT.
Chapter 1620, Impact Attenuators (pdf 1.8 mb) describes the impact attenuators that are approved for use by WSDOT.

(Old) Type 1 Beam Guardrail Design Information
WSDOT is phasing out the use of Type 1 guardrail. A primary reason for phasing out Type 1 guardrail is that all configurations of the Type 1 guardrail are not MASH- compliant (pdf 139 kb) whereas Type 31 guardrail is MASH compliant.

(Old) Type 1 Beam Guardrail Placement Cases (Removed from Design Manual in 2017) (pdf 140 kb)
(Old) Type 1 Beam Guardrail Terminals and Anchors (pdf 111kb)
(Old) Type 1 Beam Guardrail Transitions (docx 23 kb)

 SCI 100

The SCI 100 GM Smartcushion was the first MASH compliant Type 31 impact attenuator on the WSDOT QPL.

Odds and Ends
Use the length need calculation spreadsheet (xls 20 kb) to calculate barrier length of need
Type 20 and Type 21 Guardrail (pdf 83 kb) is primarily used in conjunction with Service Level 1 bridges.  Contact Bridge and Structures Office for more information.