Question This sign indicates a: Answers Railroad crossing. Pedestrian crossing. No passing zone. Explanation Yellow signs with black markings are used to warn drivers about upcoming hazards or special conditions. Round signs are used only to warn about upcoming railroad crossings. Take a FREE Practice Test Now This questions appears in the following tests: South Carolina Practice Test Oklahoma Practice Test District Of Columbia Practice Test Tennessee Practice Test Mississippi Practice Test Arkansas Practice Test Connecticut Practice Test South Dakota Practice Test Arizona Practice Test Georgia Practice Test Illinois Practice Test Alabama Practice Test Wyoming Practice Test Maryland Practice Test Kansas Practice Test Delaware Practice Test Kentucky Practice Test California Practice Test New Mexico Practice Test Wisconsin Practice Test Rhode Island Practice Test Maine Practice Test