Final answer:
The reflective orange triangle bordered with red is the universal symbol for a slow moving vehicle, signaling other drivers to slow down.
Step-by-step explanation:
The sign or symbol that communicates to roadway users that a vehicle is considered a slow moving vehicle is a reflective orange triangle bordered with red. This emblem is intended to be easily seen by drivers, signaling them that they should slow down because the vehicle ahead is moving at a lower speed than normal traffic, typically 25 miles per hour or less. This symbol is especially important in areas where vehicles such as agricultural tractors, construction equipment, or horse-drawn carriages share the road with faster-moving cars and trucks.