Yeah, it doesn't seem likely to me for someone to drive 5 hrs through town on a dozer just to get loaded up on a trailer after disposing of his phone.But nobody drives a bulldover for miles. They load it on the back of a trailer and take it to the construction site.
Another thing I have thought of is how his phone was on the whole time. It didn't go off till the SO started pinging it. I would think it likely if someone was getting rid of a phone that they would turn it off so their path or eventual location would not be readily discovered. If it had pinged off 3 towers they would have been located with it. It makes me consider they wanted the focus on the bridge or else they made a mistake and didn't realize it was there and on. We have been thinking they got to the bridge and pitched it, but possibly they caught that they were being pinged and turned it off, which happened to be while on the bridge. The same can be said if they were in a boat. Searches at the bridge have found nothing. But all we know is that is where the phone was turned off. We have simply assumed that's where it went in the water. What are the chances that just when the SO pinged it is exactly when MC or whomever had his phone arrived at the destination they planned to dispose of it?