What does a white diamond symbol on the roadway signify?

Answer: C — carpool lane

The white diamond symbol on the roadway signifies a carpool lane. These lanes are designated for vehicles with multiple passengers and are meant to promote carpooling to reduce traffic congestion and improve air quality. The diamond shape clearly communicates to drivers that they are entering a lane with specific usage restrictions, typically allowing only vehicles that meet the occupancy requirements—often a minimum of two or three occupants. This helps encourage shared rides and optimizes road usage by reducing the number of single-occupancy vehicles on the road. The other options represent different roadway features that do not use the white diamond symbol. A bike lane is usually indicated by different markings or colored lanes that specifically accommodate cyclists. Pedestrian crossings are often marked by different symbols or signs that indicate where pedestrians may safely cross the street. School zones are typically marked with flashing lights or specific signs that indicate the presence of students and reduced speed limits, rather than the diamond symbol used for carpool lanes.