Guessing that a tractor-trailer would go over before a straight truck would. More area on a 53' trailer for the wind to hit. I drove tractor-trailer for awhile back in the early 90's. Comming from Philly to Buffalo with an empty 53' trailer in high winds. Was at night, going across the Rt. 9 extension and once in awhile felt the trailer rock then a loud bang. Was fighting the wind like I had never before. Finally got close to the tunnel where they had street lights. Felt the rocking again, looked into the mirror and the left tandems of the trailer were being pushed about a foot off the road. THEN, after all that I was going across Rt. 17 in NY and hit a foot of snow. The wind would blow the trailer off the road with the tractor still in the rt lane with the rt side tandems off on the shoulder. Got that truck back to the terminal and never drove a tractor trailer again. Quit that morning. Have had straight trucks rocked back and forth pretty good. That's an eerie feeling. I drove Peterbilt's and Kw's. The Pete's seemed better in the wind than the KW's. Was told that Pete's are heavier/stronger because they use a double frame. HATED driving in wind!