I think apps have reduced my chance of causing a traffic death:
My cognitive load for driving is much less than it used to be.
I no longer need to scan my environment for street signs, store signs or exit signs. I never need to look at a physical map/notes. If I miss a turn/exit, I'll recover. I don't have to suddenly shift lanes because I'll be in the correct lane a kilometer or two before the actual exit. Confusing signs telling me which lane to use are a non-issue.
I'll also drive fewer kilometers because of optimized routing. Sometimes it's more, but that's because I'll be diverting around congestion. I can also wait out the traffic and know exactly when to leave at a time that has fewer cars on the road.
Music streaming apps mean I don't have to fumble through radio stations, or clunky physical media.