For those who wonder, including ourselves, as to why signs along Interstate 29 northbound at Interstate 129 reflect the spur in text, I have an answer. At first, I speculated that Iowa wanted nothing to do with Nebraska’s Interstate 129. The fact of the matter is that there are signs for Interstate 129 on Interstate 29, half of which do not use the shield, but only an end sign along Interstate 129 east in Iowa and no signs at all along westbound.
So what’s the deal? On a whim I wrote IowaDOT about it the other night and received a response:
We received your comment concerning the use of the interstate shield for I-129 for southbound traffic and the use of letter text for I-129 for northbound traffic on I-29.
Approximately 10+ years ago some motorists were getting confused with I-129 signing, thinking it was I-29 and taking the off ramp to US75 to Nebraska when they really wanted to stay on I-29. We thought we would try using the letter text I-129 to make it stand out different from the interstate shield of I-29.
Since then we have had a signing project on southbound I-29 and changed the letter text I-129 back to the interstate shield and have had no complaints or concerns that I’m aware of. The northbound signing on I-29 will be reviewed when we put our next project together.
Thank you for you comments.
That’s a fair enough reason as any, and its only less road mystery to be solved.
Perhaps this was the same reasoning for Interstate 126’s text signs in Columbia, South Carolina…