Flashing xenon strobe lamps were installed on locomotives in revenue service as a means of alerting motorists to the hazards they are approaching at a rail-highway grade crossing. Effectiveness of these lights in attracting motorists’ attention was evaluated. The reactions of both motorists and locomotive crews to the use of strobe lights were also evaluated. Field observations, interviews, and experiments confirmed the attention-getting value of locomotive-mounted strobe lights used in revenue service to alert motorists and suggested operational procedures and device specifications that are the subject of a separate application guideline report. Experimentation and observation of the strobe, lights under railroad operating conditions verified that these lights do not interfere with perception of trackside signals or with normal motorist and crew operations. The work reported in this document supports a technical recommendation favoring use of strobe lights on more extensive research tests in railroad operational service.