I really believe there is every likelihood that Hannah's iPhone is within throwing distance of the road, and that is probably one of things searchers are especially looking for. I believe that JLM may have smashed it within just moments of the last text being sent, but at that time he was still in a rather heavier populated area, and I don't believe he would have been careless enough to just toss it somewhere there, when he knew that within a few minutes, he would be "in the country". I also don't think he tossed any of his own clothes out his car window, and I don't really believe that LE expects to find any of HIS clothes at this point, and certainly not alongside the road. I would bet money he disposed of his clothes by either burning them or tossing them in a bio hazard bag at his work and getting rid of them that way. He MAY have kept some of Hannah's clothing, especially her top, as he apparently had kept Morgan's, so I doubt they will find any of her clothing alongside the road either, but it is certainly prudent to check as many places as they can within the area he is thought to have traveled. I bet every beer bottle and can found alongside the road gets looked at...and should. I also will not be surprised at all to learn that more remains than just Hannah's are found. Actually, I really believe that they will be. JMO
ETA...The heavy police presence for these searches at this point does seem to indicate to me that they may have found remains of more than one victim.