The posted speed limit is 60MPH

That IS a very slow posting for an intersate. All of the intersates in NM (well, there are only 3 of them) have a posted limit of 75mph. And all state highways are 65mph. These speeds are a 20mph increase from about 10 or so years back.

Weren't highway speeds generally higher a long time ago? I seem to remember my parents telling me that the general highway speed of 55 was a speed reduction set back during fuel crisis times. And that the speeds were actually much faster in the past even when cars were not as safe at high speeds as they are today. But I have no idea if that is true or if I just made that up somewhere along the line.

- trs