I carry 3@ 15 and 30 minute flares, boxed triangles and an orange vest that's gonna be changed to a reflective one today.
Saw this post and wondered about my flares and went out and checked them. OOppss, gonna be replacing 4 out of 6 flares because of leakage. All the 15 minutes I got from a parts store are bad.
I have had a couple of roadside emergencies and the first thing I do is lite a flare and set it at least 100' away from the back of the rig and then set up the triangles. That will at least warn traffic that you're out there and gives them a better target.