Lighted Guidance Tube Evaluation: Final Report

Griffith, Andrew; Eric, Brooks · 2000 · ROSA P / Oregon. Dept. of Transportation. Research Group

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Summary

This report evaluates the effectiveness of the 3M Lighted Guidance Tube (LGT) as a safety device for delineating temporary detour curves in highway construction work zones. The study was motivated by the hazards posed to night drivers by confusing traffic patterns and sharp turns, particularly when visibility is poor. The LGT, a system using optical lighting film within polycarbonate tubes mounted on concrete barriers, aims to provide continuous, positive guidance to reduce accidents. The Oregon Department of Transportation (ODOT) selected the LGT as an experimental feature for the Eddyville-Cline Hill Section project on U.S. Route 20 to assess its performance regarding vehicle speeds, accident rates, and driver perceptions. The evaluation involved a five-month service period from February to June 2000. Initial installation in late 1999 failed due to dirt accumulation inside the tubes and incorrect bi-directional lighting configuration; the system was reinstalled in February 2000 with new tubing and corrected lighting. Data collection included baseline and post-installation speed measurements using traffic recorders, accident record reviews, and a telephone survey of 210 local residents who had driven through the site at night. Speed data was analyzed for both eastbound and westbound lanes during daytime and nighttime hours, while regression analysis examined relationships between speed, traffic volume, rainfall, and LGT presence. The results regarding vehicle speeds were inconclusive. Regression analysis found no significant relationship between the presence of the LGT and vehicle speeds. In the westbound lane, average speeds decreased after installation, but this trend mirrored daytime patterns, suggesting the change was not specific to the LGT’s nighttime visibility benefits. In the eastbound lane, speeds increased post-installation. However, no accidents occurred at the site during the five months the LGT was in service, compared to two accidents (including one with fatalities) prior to its installation. The motorist survey yielded strong positive feedback: 86% of respondents stated the LGT helped them travel safely through the curve, and two-thirds reported an increased comfort level. Drivers noted that the tube improved their ability to see the curve’s layout and degree of curvature, though some initially mistook the lights for oncoming traffic. The study concludes that while the LGT did not demonstrably alter vehicle speeds, it was effective in guiding motorists and improving driver confidence through difficult work zone curves. The absence of accidents during the service period and the high percentage of positive driver feedback suggest the LGT enhances safety by providing clear visual delineation. The report notes that installation challenges, such as proper tube storage and correct bi-directional configuration, are critical for successful deployment. The LGT system was dismantled upon project completion but remains available for reuse on future ODOT projects.

Key finding

86 percent of surveyed drivers reported that the lighted guidance tube helped them travel safely through the curve section, although vehicle speed data showed no conclusive relationship with the device's presence.

Methodology

field_study

Sample size: 210

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

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• roadway lighting effects
• emergency work zone conspicuity
• perceptual countermeasures