I have a Safe-T-Plus on my DP.
First of all, get weighed and run tire pressures appropriate for your weight. I can almost guarantee that 70psi is grossly underinflated and a blowout waiting to happen. Rigs behave differently; some wander all over with lower tire pressures and some wander with higher pressures. You need to find the minimum for the weight and can run from that up to the maximum.
After finding the correct pressure an alignment would be good. Look for a Wingfoot (Goodyear) truck tire dealer; if that dealer doesn't do alignments they can refer you to someone else competent.
A couple of years ago after crossing Louisiana something was horribly wrong; I was all over the road, pulled by paving irregularities, crown and wind. Turned out the rough roads had busted the Safe-T-Plus mostly loose from its bracket and it was just hanging there. Once I got it secured I was riding on rails again.
Also, it's said to be a lifesaver in a blowout. Fortunately I don't know about that.
