That used to be big business. You don't hear much about it anymore. Is it because of GPS tracking or some other reason?

I could be wrong but I would imagine there's simply too many intermediaries in today's world for this to happen as frequently as it used to. Since the 70s-80s when highjacking was still a popular racket there's been a strengthening of state police in most places as well and more cops in general be it state, highway, or local patrolling the highways. Not to mention you're no longer ripping off just one trucking company, your'e ripping off a trucking company hired by a logistics firm who in turn was hired as a go-between for a 2nd trucking/distributing company. That accompanied by the new security measures in most trucks make this once popular racket a relic of a simpler time.

^^^feel free to correct me if I'm wrong, I've often wondered this question to myself and to the best of by researching ability this is what I've come up with

It's just not that easy anymore. Plain and simple. It still takes place, but no where near the magnitude it was way back when. It's not like theirs guys posted up at Idlewild smoking cigarettes and just waiting for a load of electronics for Best Buy to come pulling out.

In addition to the technology that made it harder, it seems like the mob felt the profit just wasn't worth the work/risk. Relatively safer ways to make more money. What's interesting is there's still plenty of mob cases that involved stolen goods.

In LCN case, Ivy answered your question. But speaking in general, it's still a lucrative business. Especially in Memphis : http://www.fbi.gov/news/videos/task-force-combats-cargo-theft-in-memphis

It's really really hard nowadays, from GPS trackers with the cargo , to fucking serial numbers, cameras, besides the fact that in the old days they could grease whoever a palms where necessary, it's just not a wise career choice anymore