Highways 5 and 65 could become Interstate 435 in the Des Moines metro

[stevashe]

Why are there three I-235s within a day's drive of each other, but only one I-635 anywhere and no I-835 at all?

For whatever reason, DOTs/FHWA/AASTHO/Whoever comes up with route numbers tend to use the lowest applicable prefix for 3di's. There are certainly exceptions, but that's why there are a ton more 1xx and 2xx interstates out there than 8xx and especially 9xx.

I do agree it would be better to use unique numbers where possible, but I don't think it's that big of a deal to duplicate 3di numbers.

[silverback1065]

Why are there three I-235s within a day's drive of each other, but only one I-635 anywhere and no I-835 at all?

For whatever reason, DOTs/FHWA/AASTHO/Whoever comes up with route numbers tend to use the lowest applicable prefix for 3di's. There are certainly exceptions, but that's why there are a ton more 1xx and 2xx interstates out there than 8xx and especially 9xx.

I do agree it would be better to use unique numbers where possible, but I don't think it's that big of a deal to duplicate 3di numbers.

it's logical start with the lowest available number and move up from there.

[SEWIGuy]

What am I missing? Where in Iowa is another 435? Is it because of 435 in the Kansas City metro? How would that be confusing?

It would be no more confusing than renumbering, say, US-6 to be a second US-70 instead.

But why reuse a number at all when there is another unused number that also fits the pattern?

Why are there three I-235s within a day's drive of each other, but only one I-635 anywhere and no I-835 at all?

Basically, I don't like duplicate route numbers of the same class.  And I'd rather break the grid than duplicate.

I don't think the Iowa DOT uses the "does kphoger like this number" test when determining these things.

[kphoger]

I don't think the Iowa DOT uses the "does kphoger like this number" test when determining these things.

I had begun to suspect as much.

[rte66man]

What am I missing? Where in Iowa is another 435? Is it because of 435 in the Kansas City metro? How would that be confusing?

It would be no more confusing than renumbering, say, US-6 to be a second US-70 instead.

But why reuse a number at all when there is another unused number that also fits the pattern?

Why are there three I-235s within a day's drive of each other, but only one I-635 anywhere and no I-835 at all?

Basically, I don't like duplicate route numbers of the same class.  And I'd rather break the grid than duplicate.

There are 2 635's; one in Dallas and the other in the KC metro.

[kphoger]

There are 2 635's; one in Dallas and the other in the KC metro.

Man, I always forget the one in Texas.