Sign, Signal, and Luminaire Supports, Utility Poles,

Trees, and Similar Roadside Features

RDG Chapter 4

Roadside Appurtenances

• Sign and Luminaire Supports

• Traffic Signal Supports

• Mailbox Supports

• Utility Poles

• Trees

crash

Stub Height Criteria

4” max.

5’ min.

Stub

Sign Supports

Types of Sign Supports

•Overhead Signs

•Large Roadside Signs

•Small Roadside Signs

Portland/Oregon street sign

Tysons/Lessburg street sign

Ground-Mounted Breakaway Signs

Wind

Strong in Moment

Vehicle ImpactWeak in Shear

Car position 1

Car position 2

7’

Uni-directional slip base

Frangible coupling

Old Mill Bottom Road Sign

Lower signs

Small Sign Supports

•Base Bending

•Slip Base

•Fracture

Breakaway Hinge Point on Slopes

Roadway

20’

7’

Safer Roads

14

2 concerns

Luminaire Supports

Types of Breakaway Luminaire Supports

• Transformer Bases

• Slip Bases

• Frangible Couplings

• Fiberglass Poles

4” Stub Requirement