In the United States, there are 6 different interstates named I-495. This is redundant and potentially confusing. Thus, I propose changing the DC Beltway to I-666, a fitting number for its hellish attributes.
Any poor soul unfortunate enough to drive on the Beltway during a time that the sun is up, or when the sun is down, can attest that the experience worse than a boat tour of the River Styx.
Furthermore, the designation I-666 still fits all of the numbering conventions. 3-digit interstates (that start with even numbers) normally correspond to loops around cities.
Instead of using I-95 as the parent highway, we should use I-66, and add the digit "6" in front to signify the loop. This would appropriately convey the message, "abandon all hope of arriving on-time, ye who enter here."