Breakaway Luminaire Pole Research
REPORT NUMBER
TRP-03-481-25
AUTHORS
Jacob Conway, Mojdeh Pajouh, Bob Bielenberg, Ronald Faller, Mohammadreza Rajaee
PUBLICATION DATE
2025-12-18
ABSTRACT
This document reports efforts to identify critical parameters and configurations for Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) compliant breakaway luminaire poles with slip bases. The project aimed to determine pole configurations with the potential to meet MASHTL-3 and recommend critical configurations for full-scale crash testing. First, a comprehensive literature review was conducted which included survey results collected from Midwest Pooled Fund state departments of transportation (DOTs), standard plans from state DOTs, and past luminaire pole testing. Numerical models using LS-DYNA were developed for luminaire poles with a 4-bolt slip base, as utilized by the Utah Department of Transportation, and were validated against the USBLM full-scale crash test series. The validated model was utilized to simulate various pole configurations with a 4-bolt slip base under MASH test designation nos. 3-60, 3-61, and 3-62 at impact angles of 0 and 25 degrees, with the vehicle impacting at the center and quarter points. Configurations included pole heights ranging from 20 to 50 ft and mast arm lengths ranging from 4 to 20 ft. The simulations were post-processed and analyzed to identify trends regarding MASH safety criteria, including occupant compartment deformation, occupant risk measures, and vehicle instability, to identify the critical parameters and configurations for slip base luminaire poles. The following trends were identified based on the simulation results: (1) no simulations exceeded MASH limits for occupant impact velocity, occupant ridedown accelerations, and roll and pitch values; (2) MASH test designation no. 3-60 impacts appeared to be more critical in terms of roof crush; (3) vehicle center impacts were found to be more critical than quarter-point impacts for roof crush; (4) multiple configurations exceeded the 4-in. roof crush limit roof under MASH test designation no. 3-60 impact conditions, (5) no occupant compartment intrusion occurred in MASH test designation nos. 3-61 and 3-62; and (6) nearly all pole configurations between 450 lb and 600 lb showed potential to meet MASH criteria. Based on these simulations results, critical pole configurations and critical impact conditions were recommended for full-scale crash testing.
KEYWORDS
Highway Safety, Crash Test, Roadside Appurtenances, MASH 2016, LS-DYNA, Breakaway Poles, Slip Base, Computer Simulation