depending on the trucks available we usually don't stand in a fend-off position but in driving direction, behind and alongside e.g. the car wrecks.
For a normal MVA on the highway with up to 5 cars we don't send out a Rescue truck, but one Engine and one Tanker from our station, and another Engine as well as Utility from one of the Volunteer FDs.
When the car wrecks are standing on the fast lane, then we position the Engine right next to them in the right lane, directing traffic onto the shoulder. The Tanker is positioned in some distance behind the Engine in the same lane. The Tanker pulls a traffic safety trailer which is 13 ft high when set up and then has directional arrows (both a simple reflective sign which can be turned into 3 different positions as well as lighted arrows above). As soon as the Engine and Utility of the VFD arrive the position themselves again in the same lane in some distance, and also the Utility sets up a traffic safety trailer. The distance between the single units is covered with cones, and the left lane is kept free for further emergency vehicles arriving
This is how it might look like:
Chris, this is great table talk shop. I have just in the past two months completed the FEMA TIM's Class. I highly recommend that you or someone from your department take this class. It clearly points out what your state DOT (Department of Transportation) has adopted into law for Emergency Vehicle (Police, Fire, EMS, and DOT) while operating on highways in emergency and none emergency mood. Every state has to follow and or adapt something close to or better than the Federal Government. Depending what type of fire apparatus that responds to these incidents various on how you position your apparatus. Very enlightening class and an awesome job.