Besides I-71 and I-78, which I've clinched, the following are 2di I've traveled at least 60% of:
I-26: 218/306 (71%), missing portion north of I-40/240
I-74: 285/417 (68%), missing portion west of I-55
I-39: 202/306 (66%), missing portion north of I-90/94
I-76: 288/435 (66%), missing portions between I-79 and I-376, and east of US 15
I-68: 71/113 (63%), missing portion west of US 40/US 219
I-77: 389/613 (63%), missing portions between I-64 and US 30, and north of I-76
I-75: 1118/1786 (62%), missing portions south of Florida's Turnpike and north of I-94
I'll look at my 3di later.