The problem with this issue is theres the LAW of Torts and its well settled but then theres the practical and economical issue.
The LAW says if an object is unsecured and flies off a truck and causes you damage, the truck owner/operator is obviously liable well DUH
The LAW says the planitiff has the burden of proof and to prevail has to do so by a "preponderance of the evidence" NOW that obviously makes it harder for the Plaintiff in a "he said she said" scenario. THATS WHY THE TRUCKING COMPANIES DONT RUSH OUT AND PAY ANYONE AND EVERYONE WHO FILES A CLAIM.
Thw way I would deal with it personally is to get the trucks license and any other ID Info,,,,,,File a police report (note exact time and location etc),,,,,,,,, Go to a winshiled repair shop right away and get their opinion of cause and type of damage and estimate to repair in writing,,,,,,,,,Notify my insurance carrier armed with a copy of the police report and estimate and opinion from the winshield repair shop,,,,,,,,,SIT BACK AND WAIT N SEE WHAT HAPPENS AND WHAT YUOR INSURANCE CARRIER HAS TO SAY,,,,,,,get it fixed which may well turn out to be solely at your expense due to all that above
NOTE The law of Torts which is very well settled over many years and NOT the owner determines who is liable and who is not liable in many of these situations. IE most owner signs such as "NOT responsible for accidents" arent worth a hill of beans and are profitable ONLY for the sign makers it would appear lol. It may have a bluff or intimidation factor for some I suppose, they can have some legal force (notice, assumption of risk etc etc) but thats for a small limited area.
Best wishes yall, stay back from trucks now
"Stop Global Whining"
John T BSEE,JD Attorney at Law