Carlo repeatedly beating his wife, in turn sonny coming to beat the shit out of carlo every time he did that, and in some random chance sonny drives the car without his men, and Barzini's men standing there ready with guns....
This plan sounds ridiculous to me. Barzini would send his men to the toll booth on several occasions and call up carlo to beat his wife, and then his men would be waiting in the booth for hours together, looking for sonny to come ,and return home disappointed. I am sure one of Barzini's men would have got so pissed off with this scheme, that he would have hatched Barzini's murder than pursue this funny plan.

Probably not as far-fetched as you try to make it. If you read the book, Carlo gradually beat up Connie a little more each time. At first, it was just a black eye and then a few whacks. But the beating that Carlo gave Connie that lead to Sonny's death was severe.

I doubt very much that Barzini's men were waiting for Sonny multiple times. Carlo was most likely told to ensure that the beating would be sufficient enough to incite Sonny into a blind rage that clouded his judgment and forget about his safety as the temporary Don.

Yes, it was probably perfectly timed. Barzini must have told Carlo, "Really beat her up this time so she can go crying to her mother." Carlo may even have been in the apartment when Connie made the phone call. If he did hear her calling the Mall, he would then be reasonably sure that Sonny'd lose his temper and get in his car. At that point, he might have contacted the hit men for the go-ahead--so they might not have been waiting for hours.
BTW: Though Barzini lured Carlo into this plot, Tattaglia's men may have been the actual trigger-pullers. Barzini did a good job of covering his tracks because the Don didn't learn that "it was Barzini all along" until later.

Don't forget that in the novel, Carlo was drunk and passed out when Connie makes the call. Or at least that's what we're lead to believe, so he would have had to call immediately after beating Connie up and before passing out. Because when Tom calls Connie's apartment, she answers and is terrified to wake Carlo up. It takes 5 minutes to rustle Carlo from his slumber and then Hagen breaks the news that Sonny was killed.

Nah, Those were Barzini's men that pulled the trigger. Mike said to carlo,"You fingered Sonny for the Barzini people."