stop, look, and listen

to exercise caution, especially at street corners and railroad crossings, by stopping, looking to the left and to the right, and listening for approaching vehicles or a train. Sally's mother trained her to stop, look, and listen at every street corner. It is a good practice to stop, look, and listen at a railroad crossing.

Railroad crossing warning. Before the installation of gates and flashing lights, a road that crossed a railroad track had a post on which was an X. On the crossbars was written “stop look listen,” a phrase attributed to an anonymous engineer who through that immigrants who read only rudimentary English would be able to understand the three words and heed their warning. Now automatic devices warn motorists and pedestrians to be mindful of approaching trains.