Most lightly traveled interstate in your state

[michravera]

As a singular route I would imagine I-505 is the big winner in California.

CalTrans publishes the traffic counts. I might have guessed I-505, but the 2017 count shows around 12K AADT near the split and junction with I-5 or portions of I-8 which shows a bit less than 8K AADT roughly at the San Diego-Imperial County line.

[gonealookin]

As a singular route I would imagine I-505 is the big winner in California.

CalTrans publishes the traffic counts. I might have guessed I-505, but the 2017 count shows around 12K AADT near the split and junction with I-5 or portions of I-8 which shows a bit less than 8K AADT roughly at the San Diego-Imperial County line.

I was looking at those same tables and some of the Caltrans reports have "left align/right align" splits.  Not sure exactly what that terminology means but going by context it looks like I-8 in that vicinity is actually 2 x 8K = 16K.  I think Max R. is right about I-505, whose 11,200 at the lowest edges out I-40's low of 11,700.

[ari-s-drives]

As a singular route I would imagine I-505 is the big winner in California.

CalTrans publishes the traffic counts. I might have guessed I-505, but the 2017 count shows around 12K AADT near the split and junction with I-5 or portions of I-8 which shows a bit less than 8K AADT roughly at the San Diego-Imperial County line.

I was looking at those same tables and some of the Caltrans reports have "left align/right align" splits.  Not sure exactly what that terminology means but going by context it looks like I-8 in that vicinity is actually 2 x 8K = 16K.  I think Max R. is right about I-505, whose 11,200 at the lowest edges out I-40's low of 11,700.

I went through the 2018 data and averaged out all of the "ahead_aadt" data of all of the segments for each interstate and found that over all of its segments, I-40 has the lowest average AADT per segment.

I am not 100% sure how to interpret the data, so please do let me know if I took the wrong approach.

https://drive.google.com/file/d/1SlWOjMIhL1bEHWfeHx0HcI4iLswzejZ9/view

[STLmapboy]

Ozarkman already mentioned 155, which is definitely 3di. For 2di it is probably I-49 between Carthage and Harrisonville (according to https://www.modot.org/traffic-volume-maps), but I-35 north of Cameron has some very light numbers as well.

[mrcmc888]

Delaware only has three interstates, so it's not really "lightly-traveled", but the one with the lowest AADT is I-495 with a minimum of 25091.

[Brandon]

Pretty sure IL is I-180. Just have a feeling...

Y'think?  I-180 is by far and away the lightest traveled interstate (or freeway for that matter) in the state.
http://www.gettingaroundillinois.com/gai.htm?mt=aadt

[Roadgeekteen]

Pretty sure IL is I-180. Just have a feeling...

Y'think?  I-180 is by far and away the lightest traveled interstate (or freeway for that matter) in the state.
http://www.gettingaroundillinois.com/gai.htm?mt=aadt

It might be the lightest traveled interstate in the country.

[zzcarp]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

[Roadgeekteen]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

[Great Lakes Roads]

Indiana? Probably I-69 between Evansville (north of I-64) and Bloomington in southern Indiana...

[DandyDan]

For Iowa, I assume it's I-880. In Nebraska, I assume it is I-80 west of I-76.

[JayhawkCO]

Pretty sure IL is I-180. Just have a feeling...

Y'think?  I-180 is by far and away the lightest traveled interstate (or freeway for that matter) in the state.
http://www.gettingaroundillinois.com/gai.htm?mt=aadt

It might be the lightest traveled interstate in the country.

This is data from 2013 that I posted a long time ago, but other than unsigned and international crossings, it's I-90 in Wyoming.

Lowest AADT 2dis
1. I-A2 AK 237 @ mile 145
2. I-A1 AK 307 @ 256
3. I-A4 AK 1080 @ 104
4. I-95 ME 1682 @ 300
5. I-15 MT 1790 @ 396
6. I-89 VT 2000 @ 130
7. I-91 VT 2100 @ 177
8. I-90 WY 2198 @ 59
9. I-10 TX 2652 @ 364
10. I-25 WY 2718 @ 299
11. I-29 ND 2980 @ 217
12. I-15 ID 3000 @ 181
13. I-A3 AK 3021 @ 52
14. I-75 MI 3100 @ 375
15. I-94 MT 3170 @ 241
16. I-70 UT 3275 @ 104
17. I-90 MT 3420 @ 520
18. I-25 NM 3630 @ 453
19. I-94 ND 3868 @ 0
20. I-29 SD 4460 @ 227
21. I-80 NV 4600 @ 404
22. I-20 TX 4804 @ 38
23. I-81 NY 4998 @ 180

Lowest AADT 3dis
1. I-180 IL 2200 @ mile 10
2. I-185 SC 3400 @ 12
3. I-115 MT 3630 @ 0
4. I-229 MO 4228 @ 6
5. I-680 IA 5700 @ 19
6. I-172 IL 6300 @ 12
7. I-890 NY 7053 @ 8
8. I-781 NY 7297 @ 0
9. I-155 MO 7312 @ 0
10. I-335 KS 7320 @ 137
11. I-380 IA 7700 @ 65
12. I-476 PA 7930 @ 124
13. I-129 NE 8250 @ 0
14. I-495 ME 8680 @ 0
15. I-795 NC 8900 @ 7
16. I-505 CA 8900 @ 30
17. I-155 IL 8900 @ 0
18. I-520 SC 9300 @ 23
19. I-790 NY 9324 @ 1

Chris

[Flint1979]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

[JayhawkCO]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

[Flint1979]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

Taking I-25 north to CO-14 to US-287 up to I-80 west is quicker and shorter. Taking the route you are talking about is a little further and takes a little longer.

[JayhawkCO]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

Taking I-25 north to CO-14 to US-287 up to I-80 west is quicker and shorter. Taking the route you are talking about is a little further and takes a little longer.

What if you live in Arvada? Lakewood? Golden?  All places in the metro area where that would not be true. (Getting off topic for this thread though.)

Chris

[Flint1979]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

Taking I-25 north to CO-14 to US-287 up to I-80 west is quicker and shorter. Taking the route you are talking about is a little further and takes a little longer.

What if you live in Arvada? Lakewood? Golden?  All places in the metro area where that would not be true. (Getting off topic for this thread though.)

Chris

All three of those places are the same route as Denver to SLC.

[JayhawkCO]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

Taking I-25 north to CO-14 to US-287 up to I-80 west is quicker and shorter. Taking the route you are talking about is a little further and takes a little longer.

What if you live in Arvada? Lakewood? Golden?  All places in the metro area where that would not be true. (Getting off topic for this thread though.)

Chris

All three of those places are the same route as Denver to SLC.

Google maps disagrees, but as I said, off topic for this thread.  Either way, I-70, a major trucking thoroughfare having nearly the same traffic as rural I-76 is still surprising.

Chris

[MikieTimT]

Ozarkman already mentioned 155, which is definitely 3di. For 2di it is probably I-49 between Carthage and Harrisonville (according to https://www.modot.org/traffic-volume-maps), but I-35 north of Cameron has some very light numbers as well.

Well most people who actually travel I-49 in the Joplin/Carthage area actually turn off of it on (or just stay on it for northbound I-49) MO-171/249 as it's a better TOTSO than the crappy cloverleaves that I-49 has with I-44.  Only those heading to I-44 east on southbound I-49 and vice versa actually use that stretch other than local traffic.  If they'd ever actually do a proper Interstate to Interstate interchange on Exit 53, I could see MoDOT moving I-49 over to it as it's quicker for anything other than the aforementioned movements.

[TEG24601]

In WA, I'm going to assume I-705.

[bing101]

As a singular route I would imagine I-505 is the big winner in California.

I would imagine I-780 in California too given that these interstates are not as jammed as I-80 though.

[nexus73]

I-82 in Oregon would be my guess for the Beaver State if the whole route is to be counted.  There just is not that many miles on it with there being alternate routes to connect with the bridge at the border from both eastbound and westbound traffic, which makes Oregon's section of I-82 rather redundant.

Rick

[ari-s-drives]

As a singular route I would imagine I-505 is the big winner in California.

I would imagine I-780 in California too given that these interstates are not as jammed as I-80 though.

Overall 780 appears to be the third-least-travelled with an average of 58K aadt per segment versus 21K for 505 and 16K for 40

data

[US 89]

In Colorado, it's I-76 northeast of Sterling to the Nebraska line. CDOT reports just southwest of Julesburg an AADT of 7800.

After that, I was surprised to see I-70 at the Utah line has an 8300 AADT.

Probably mostly Denver-Salt Lake City/Las Vegas/LA travel.

How does SLC come into the picture on I-70 at the Utah-Colorado state line?

Depending on traffic and where you are in Denver, the quickest way from Denver to SLC is I-70 west into Utah and then US 6 through Price to I-15.

Chris

Taking I-25 north to CO-14 to US-287 up to I-80 west is quicker and shorter. Taking the route you are talking about is a little further and takes a little longer.

What if you live in Arvada? Lakewood? Golden?  All places in the metro area where that would not be true. (Getting off topic for this thread though.)

Chris

All three of those places are the same route as Denver to SLC.

Google maps disagrees, but as I said, off topic for this thread.  Either way, I-70, a major trucking thoroughfare having nearly the same traffic as rural I-76 is still surprising.

Chris

As somebody who has made the Denver-Salt Lake drive multiple times, depending on your exact O/D within the Denver and Salt Lake areas, it's generally more or less the same time between the two cities with a slight edge to I-80. But even if 80 is faster, there are plenty of reasons to take 70 instead. For one, the I-70 route is much more fun as a driver, since it takes you through all kinds of cool Rocky Mountain terrain like Glenwood Canyon. I-80 through Wyoming is relatively flat and uninspiring, and it gets old after about 15 minutes - especially if you've gone that way multiple times before.

Also, believe it or not, I-70 is a more reliable route in winter despite its higher elevation. Sure, you're fighting skiers and mountain pass traffic, but because of the relatively flat profile of I-80 across Wyoming, it tends to experience all sorts of blizzards that will shut down the highway entirely. I-70 probably gets more snow, but in my experience it rarely closes completely. So while sitting in ski traffic on 70 sucks, I'd take that any day over spending the night in Rawlins or something because a blizzard closed I-80.

[dlsterner]

For Maryland it looks like it would be I-68 near the MD/WV border - between MD 42 and US 219, AADT of 13,260

For grins, I also looked up the highest - I-270 just north of its split before I-495 - an AADT of 265,633

Neither of which were surprising.

Edit:  Corrected fumble-fingered typing - of course 496 should be 495