This report summarizes the evaluation of the Lighted Guidance Tube (LGT), a 3M product used to delineate a temporary detour curve section on the Eddyville-Cline Hill Section construction project. The 3M LGT system can reduce accidents on highway curves or through construction work zones by providing motorists with continuous, positive guidance along the roadway.
The installation of the LGT proved to be more challenging then envisioned, primarily because the crew was unfamiliar with the device. The LGT was first installed in December 1999 but did not work as designed. This was because the tube portion of the LGT had been stored for two weeks outside at the job site. Dirt and water had accumulated on the interior of the tube, thus reducing its optical light transmission characteristics. When 3M was consulted, they provided additional tubing for replacement. The new tube was reinstalled in February 2000.
During its five months in service, the LGT was evaluated to observe its effect on vehicle speeds, accidents, and driver perceptions. The effect on vehicle speeds was inconclusive; no relationship between the presence of the LGT and vehicle speeds could be established. During the LGT’s time in service, no accidents occurred at the site. In a survey of local residents, 86% of the drivers surveyed said the LGT helped them travel through the curve section. The majority of comments received from the survey respondents was very positive. Generally, remarks focused on how much the LGT helped drivers see the layout of the curve.
The LGT remained in service until June 2000 when it was dismantled to accommodate the completion of the new highway alignment. The LGT is available for reuse on future Oregon Department of Transportation projects.