POV response. 3 vehicle PIA/vehicle fire

Dispatched to a multi-vehicle PIA with 1 possibly starting on fire. Dispatched later stated there were individuals who were trapped inside 1 of the vehicles. While en route, I made the decision to put AeroMed on standby. Dispatch advised that 1 vehicle was confirmed on fire with at least 2 others lighting up and that the trapped individuals were able to get out. Once we got a little closer, we could see a large plume of black smoke coming from the accident. Another local department was clearing an accident of their own a few miles away and asked if we wanted them to respond. From the information we had, I made the call to have them respond as mutual aid. Due to construction on the highway, the Eastbound lane was completely blocked off, and vehicles were exiting the highway by driving the wrong way up the on ramp. Once on scene, I advised dispatch that at least 2 vehicles were on fire. Once I got closer, I observed 2 vehicles that were fully involved involved and 1 vehicle with the engine compartment on fire. I told our incoming engine and any other incoming to enter the Westbound lanes and come in into incoming traffic. PD had 1 lane shut down already in the opposite direction. Our engine showed up, and we pulled a line. Our mutual aid showed up at about the same time. 3 vehicles were involved, and luckily, there were no serious injuries reported.