What state has the highest percentage of six+ lane interstates? Lowest?

[Roadgeekteen]

For most, Delaware maybe? Although I think that I-95 through Wilmington is only 4 lanes.

For least, Wyoming?

[TheHighwayMan3561]

Wyoming would probably be a high contender for lowest percentage of 6-laning. Not even the I-25/80 interchange has six lanes on either freeway. with some aux lanes on I-25 north of 80. There might be some truck lanes on I-80 in the steeper parts of the state, though.

[US 89]

There might be some truck lanes on I-80 in the steeper parts of the state, though.

Wyoming is pretty good at providing truck climbing lanes where they're needed compared to a lot of other states, so there are a fair amount of them along I-80 throughout the state ... but that only gets you to 5 lanes, since those are generally only on the uphill side. I'm 80% sure there is nowhere in the state with a third lane in both directions, other than a brief aux-lane situation like mentioned on 25.

[SkyPesos]

Kentucky is up there, with both I-65 and I-75 almost entirely 6 laned.

Florida is another one in my mind, with I-75 6-laned all the way down to Naples. I'm guessing I-4 doesn't have any 4-lane sections, and I-95 is 6-laned in most of its route in the state.

[JayhawkCO]

There might be some truck lanes on I-80 in the steeper parts of the state, though.

Wyoming is pretty good at providing truck climbing lanes where they're needed compared to a lot of other states, so there are a fair amount of them along I-80 throughout the state ... but that only gets you to 5 lanes, since those are generally only on the uphill side. I'm 80% sure there is nowhere in the state with a third lane in both directions, other than a brief aux-lane situation like mentioned on 25.

Pretty sure you're right with this being probably the closest argument for a stretch of 6-laning.

Chris

[Roadgeekteen]

So Wyoming is the least. Is Delaware the most? Or is it Rhode Island?

[Great Lakes Roads]

Are there any six-lane sections in Vermont? I am going to say that there aren't any.

[jeffandnicole]

Some rough numbers for Delaware (these are approximate, maybe a fraction off):

I-95: 23.4 miles: 14.7 miles are 6+ lanes; 8.7 miles are 4 lanes
I-495: 11.5 miles: 10.5 miles are 6 lanes.  About 1 mile total is less than 6 lanes: 4 lanes (near the PA border), along with about 1/4 mile on 495 South at 95 being 2 lanes.
I-295: 5.1 miles; About 3 miles is 6+ lanes.  While 295 South is 3 lanes almost all the way to I-95, I-295 North is only 2 lanes for nearly 2 miles after taking off from I-95.

So for Delaware:  About 40 miles total of Interstate Mileage.  About 28.2 Miles is 6+ lanes, for about 70.5%.

[Roadgeekteen]

Are there any six-lane sections in Vermont? I am going to say that there aren't any.

No I don't think so.

[jeffandnicole]

New Jersey is way up there.  There's about 431 miles or so of Interstate Highway in NJ.

I-295's southern portion has about 13 miles of fewer than 6 lanes.

About 33 of I-195's 35 miles is fewer than 6 lanes.

Less than 4 miles of I-80 is fewer than 6 lanes.

A few miles of I-78 (Newark Extension) is fewer than 6 lanes.

A few miles of I-280 is fewer than 6 lanes.

(And give or take a few other miles of highway I may have excluded)

So, let's say around 56 miles of Interstate highway in NJ is fewer than 6 lanes.  375 miles of NJ's 431 miles of Interstate highway is 6 lanes or greater, or about 87%.

[Roadgeekteen]

New Jersey is way up there.  There's about 431 miles or so of Interstate Highway in NJ.

I-295's southern portion has about 13 miles of fewer than 6 lanes.

About 33 of I-195's 35 miles is fewer than 6 lanes.

Less than 4 miles of I-80 is fewer than 6 lanes.

A few miles of I-78 (Newark Extension) is fewer than 6 lanes.

A few miles of I-280 is fewer than 6 lanes.

(And give or take a few other miles of highway I may have excluded)

So, let's say around 56 miles of Interstate highway in NJ is fewer than 6 lanes.  375 miles of NJ's 431 miles of Interstate highway is 6 lanes or greater, or about 87%.

Dang all of I-80 and I-78 west of I-287 is 6+ lanes?

[Dirt Roads]

West Virginia

• I-64 six lanes from Exit 11 (WV-10 Hal Greer Blvd) to Exit 15 (US-60 East Huntington) — 3.5 miles
• I-64 six lanes from Exit 28 (Milton) to about mile marker 43 — 15.5 miles
• I-64 six lanes from Exit 45 (WV-25 Nitro) to Exit 59 (I-64/I-77) — 14.1 miles
• I-64/I-77 six lanes from Exit 101 (I-64/I-77) to Exit 98 (35th Street Bridge) — 2.7 miles
• I-77 six lanes from Exit 101 (I-64/I-77) to Exit 104 (I-77/I-79) — 2.0 miles
• I-77 six lanes from Exit 48 (US-19/Corridor L) to about mile marker 45.5 — 2.4 miles
• I-81 six lanes from Exit 12 (WV-45 Winchester Ave) to Exit 23 (US-11 Falling Waters) — 11.8 miles
• I-79 six lanes from Exit 117 (WV-58 Anmoore) to Exit 125 (WV-131 Saltwell Road) — 7.1 miles
• I-79 six lanes from Exit 135 (CR-64 Pleasant Valley) to Exit 137 (WV-310 Downtown Fairmont) — 3.3 miles
• I-68 six lanes from Exit 0 (I-79/I-68) to Exit 1 (US-119 University Avenue) — 0.8 miles

Since West Virginia is on the low number side, just to be fair the tidbits should be added to the total mileage:

• I-79 six lanes from Exit 148 (I-79/I-68) to Monongahela River — 0.4 miles
• I-70 six lanes from Exit 1B (US-250) to Exit 1A (US-40/WV-88 Oglebay Park) — 0.6 miles
• I-70 six lanes from Exit 2B (CR-70/1 Washington Avenue) to Exit 4 (WV-88/US-40 Elm Grove) — 1.9 miles
• I-70 six lanes from Exit 5A (I-70/I-470) to Exit 5B (US-40 Triadelphia) — 0.5 miles

I-470 truck lanes over Wheeling Hill give us five lanes from Exit 1 (US-250/WV-2) to I-70, but not 6 lanes.
Note that the ramps between I-79 and I-68 are two lanes on each leg of the wye, and technically not a six lane highway.

Total six-lane Interstate mileage:  66.6 miles out of 545.9 total (12.2%).  And WVDOH has now broken ground to connect between Scott Depot and Nitro.

[vdeane]

Are there any six-lane sections in Vermont? I am going to say that there aren't any.

No I don't think so.

There are some sections with aux lanes on I-91.  19-20 is a typical six lanes, but 10-11 is interesting; each direction has three lanes, but not at the same time.

[CtrlAltDel]

I once compiled the following information, which should be germane, although perhaps a bit skewed given that there are roads with 4 or more lanes per direction. That said, I'm not sure why there are places with an average less than 2, which shouldn't be possible, but here you go:

Code Select Expand


Interstate Interstate Lanes Per State
Miles Lane Miles Direction

  431 2,862 3.3 New Jersey
   41    261 3.2 Delaware
2,456 14,785 3.0 California
  480 2,763 2.9 Maryland
   69    390 2.8 Rhode Island
  566 3,212 2.8 Massachusetts
  346 1,863 2.7 Connecticut
1,244 6,598 2.7 Georgia
  764 3,972 2.6 Washington
1,498 7,622 2.5 Florida
1,572 7,967 2.5 Ohio
1,241 6,018 2.4 Michigan
1,117 5,388 2.4 Virginia
1,731 7,904 2.3 New York
  938 4,257 2.3 Utah
1,140 5,103 2.2 Tennessee
  843 3,755 2.2 Kentucky
2,182 9,693 2.2 Illinois
  225    992 2.2 New Hampshire
  851 3,736 2.2 South Carolina
  913 3,995 2.2 Minnesota
3,476 15,155 2.2 Texas
  742 3,204 2.2 Wisconsin
  727 3,124 2.1 Oregon
  953 4,049 2.1 Colorado
1,169 4,959 2.1 Arizona
  930 3,939 2.1 Oklahoma
  874 3,698 2.1 Kansas
  482 2,032 2.1 Nebraska
  549 2,316 2.1 West Virginia
  367 1,529 2.1 Maine
1,263 5,269 2.1 North Carolina
  781 3,226 2.1 Iowa
  934 3,836 2.1 Louisiana
1,000 4,100 2.1 New Mexico
  678 2,768 2.0 South Dakota
1,852 7,553 2.0 Pennsylvania
  596 2,415 2.0 Nevada
  612 2,476 2.0 Idaho
  571 2,297 2.0 North Dakota
  914 3,655 2.0 Wyoming
1,191 4,765 2.0 Montana
  320 1,280 2.0 Vermont
  700 2,760 2.0 Arkansas
  999 3,935 2.0 Alabama
1,285 5,011 1.9 Indiana
1,386 5,385 1.9 Missouri
  806 2,882 1.8 Mississippi


[Great Lakes Roads]

Okay, let's take a look at Indiana's interstates with six + lane interstates.

For I-64, only the stretch between Exit 121 (I-265 interchange) and Exit 123 (New Albany exit) is six lanes.

For I-65, several stretches have 3+ lanes each way with more either currently under construction or planned (going from south to north): between the KY state line to north of the Memphis Road interchange (Exit 16), north of the US 50 interchange (Exit 50) to north of the IN SR 58 interchange (Exit 64), south of the SR 44 interchange (Exit 90) to the South Split interchange (Exit 110), between the splits, from the North Split interchange (Exit 112) to the I-465 interchange (Exit 123), from the I-865 interchange (Exit 129) to north of IN SR 32 interchange (Exit 140), from south of the IN SR 38 interchange (Exit 168) to north of the IN SR 25 interchange (Exit 175), and from south of IN SR 2 interchange (Exit 240) to the I-80/94 interchange (Exit 259).

For I-69, three spots have 3+ lanes: from the IN SR 37 interchange (Exit 114) to the Sample Road interchange (Exit 125), from the I-465 interchange (Exit 200) to north of the IN SR 9 north interchange (Exit 226), and from south of the US 24 interchange (Exit 302) to north of the SR 1 interchange (Exit 316).

For I-70, there are only three spots that have 3+ lanes each way with more to come in the following years: from the former SR 267 interchange (Exit 66) to the South Split interchange (Exit 80), between the splits, and from the North Split interchange (Exit 83) to Mt. Carmel Road (Exit 96).

For I-90 (ITR), the first three miles and from the IN SR 912 interchange (Exit 10) to the I-94 interchange (Exit 21) are three lanes each way.

All of I-94 in Indiana has 3+, so make that 46 miles. Also, I-465 has 3+ lanes (with the exception of the I-865 interchange where it drops to four lanes).

I-80 runs with I-94 for 16 miles and I-74 runs with I-465 for 20 miles.

In total, we have about 330 miles of interstates that are 3+ lanes each way, and that's about 22.62%.

[webny99]

New Jersey is way up there.  There's about 431 miles or so of Interstate Highway in NJ.
...

Less than 4 miles of I-80 is fewer than 6 lanes.

A few miles of I-78 (Newark Extension) is fewer than 6 lanes.

Dang all of I-80 and I-78 west of I-287 is 6+ lanes?

Yes. Both of them are decent roads and New Jersey has done their share of widening up to the PA line. Now it's up to PA to do their share of widening. PA's portions of I-78 and I-80 near the NJ border are some of the most terrible four-lane interstates in the country. Some progress is finally being made on I-80 in Monroe County, PA, although it really needs to be six lanes all the way to I-380.

[Rick Powell]

That said, I'm not sure why there are places with an average less than 2, which shouldn't be possible

Places like the Franconia Notch in NH and the former 2-lane interstates in Maine, Utah and Idaho would possibly skew the number less than 2 within a state if they exceeded the miles of greater than 4-lane sections, but I can't think of any "less than 4 lane" interstates in those states you list with an average less than 2.

[froggie]

Are there any six-lane sections in Vermont? I am going to say that there aren't any.

No I don't think so.

There are some sections with aux lanes on I-91.  19-20 is a typical six lanes, but 10-11 is interesting; each direction has three lanes, but not at the same time.

If we're including auxiliary lanes, then it's worth noting there are auxiliary lanes in Wyoming as well, specifically I-25 in both Casper and Cheyenne.

[SkyPesos]

I'll check Ohio's percentage based on Google maps satellite images. Following distances exclude auxiliary/exit only lanes. Concurrencies will only count into one route.

I-70: 83/225 miles 6 laned.
I-71: 185/245 miles. Concurrencies with I-70 and I-75 counted under their totals.
I-74: 0/16 miles. Concurrency with I-275 counted under I-275's total.
I-75: 130/212 miles
I-76: 4/79 miles. Concurrency with I-77 counted under I-77's total.
I-77: 48/163 miles
I-80: 169/237 miles
I-90: 44/101 miles. Concurrency with I-80 counted under I-80's total.
I-270: 55/55 miles
I-271: 22/40 miles
I-275: 47/56 miles
I-277: 4/4 miles
I-280: 5/12 miles
I-470: 0/7 miles, though the WB direction have a third climbing lane.
I-471: Excluded from the count, as it's a glorified ramp in the state
I-475: 4/20 miles
I-480: 26/38 miles. Concurrency with I-271 counted under I-271's total
I-490: 2/2 miles
I-670: 10/10 miles
I-675: 15/26 miles
I-680: 5/16 miles

Total: 858/1564 mi = 54.86% of interstate mileage in Ohio with 6+ lanes

[sprjus4]

New Jersey is way up there.  There's about 431 miles or so of Interstate Highway in NJ.
...

Less than 4 miles of I-80 is fewer than 6 lanes.

A few miles of I-78 (Newark Extension) is fewer than 6 lanes.

Dang all of I-80 and I-78 west of I-287 is 6+ lanes?

Yes. Both of them are decent roads and New Jersey has done their share of widening up to the PA line. Now it's up to PA to do their share of widening. PA's portions of I-78 and I-80 near the NJ border are some of the most terrible four-lane interstates in the country. Some progress is finally being made on I-80 in Monroe County, PA, although it really needs to be six lanes all the way to I-380.

The western 4 miles of I-80 in New Jersey is still 4 lanes.

[Tom958]

Georgia's pretty high. I got 74%, which I'm not really sure about,  but I don't have time to check my work. Still: virtually all of 75, 95, 285, and 476; half of 85, nearly half of 20. Could be.

[thspfc]

Wisconsin is in probably on the low end, the only 6+ lane rural Interstate segments are I-41/94 from the Illinois border to the Milwaukee area, and I-39/90+94 from the Illinois border to Portage.

[jmacswimmer]

Tried crunching the numbers for Maryland:

I-68: 0/82 (there are plenty of climbing lanes leading to 5-lane situations, however)
I-70: 34/94 (most of the distance between Frederick & BaltimoreBeltway, also some 5-lane situations between Hagerstown & Frederick not included)
I-81: 1/12 (this is a new addition following completion of the widened Potomac River Bridge and 6-laning continued from WV up to exit 1)
I-83: 15/33 (almost everything from Shawan Rd south, exceptions are the ramps at each I-695 interchange and 2 short portions downtown where northbound briefly shrinks to 2 lanes to allow the next onramp to continue as the 3rd lane)
I-95: 108/109 (everything except for the flyover I-95 SB uses to merge into I-495)
I-97: 9/17 (northern half)

I-270: 21/35 (most of Montgomery County, also including I-270 spur's mileage)
I-370: 2/2.5 (east of I-270)
I-195: 0/4.7 (5 lanes MD 170 to MD 295, however)
I-295: 0.5/0.8 (where the I-95/495 ramps join? Also not sure where I-295 officially begins)
I-395: 0/1.5 (unless you want to count the brief piece between I-95 & MLK Blvd, but I think of those as auxiliary lanes)
I-495: 15.9/16 (figured I'd be thorough and ding exit 34, where EB shrinks to 2 lanes for a couple hundred feet before I-270 enters on the left)
I-595: 19/19 (first 100%-er!)
I-695: 31/31 (being technical and omitting the MD 695 portion - including MD 695, totals would change to 34/51)
I-795: 4/9 (southern half)
I-895: 0/15 (unless you want to count the I-95 ETL ramps beginning at the northern terminus...)

Overall: 260.4/480.5 = 54.2%  (with MD 695 included: 263.4/500.5 = 52.6%)

[Crown Victoria]

Pennsylvania's six-lane interstates:

I-70: 3.5/84 miles, independent of the PA Turnpike
I-76: 70/352 miles. Two widening projects currently under construction totaling about another 10 miles or so with two more set to begin construction within the next year or so, and several more widening projects in design.
I-78: 12/75 miles.
I-79: 9/181 miles, not counting concurrency with I-70
I-80: 0/311 miles. Projects to widen to six lanes near Stroudsburg are in design.
I-81: 13/232 miles. There are studies underway for the widening of I-81 between MD and I-78. Projects in design for the Wilkes-Barre/Scranton area.
I-83: 3/51 miles. Approximately 3 additional miles presently under construction, with additional projects to as many as 10 lanes in design.
I-84: 0/55 miles.
I-86: 0/7miles. Formerly a super-2.
I-90: 0/46 miles.
I-95: 40/44 miles. Projects in design to widen the rest of I-95's PA mileage except for within the I-476 interchange and the flyovers for the Turnpike interchange.
I-99: 0/86 miles.
I-176: 0/11 miles.
I-180: 0/29 miles.
I-276: 25/30 miles. Projects in design to widen the rest of I-276 not presently at 6 lanes.
I-279: 5/13 miles.
I-283: 0/3 miles.
I-295: 0/10 miles. Approximately 2 miles under construction approaching the Scudder Falls Bridge, with another mile or so in design at the I-95/PA Turnpike interchange.
I-376: 12/85 miles.
I-380: 0/28 miles.
I-476: 29/132 miles. Approximately 6 miles to begin construction later this year, with another 12 miles in design.
I-579: 0/2 miles.
I-676: 1/2miles.

222.5/1869 miles. Approximately 12% of PA's interstate mileage is presently six lanes or greater. As noted, there are several projects presently under construction or in design which will increase this percentage.

[US 89]

Might as well do the math for Utah:

I-15: 116.1/400.8 - I did count between exits 5 and 6 in St George since it's a c/d setup as opposed to a simple auxiliary lane. I believe plans are in the works to six-lane even more of 15 through that area in coming years.
I-70: 0/231.9
I-80: 29.3/194.8 - not counting I-15 overlap
I-84: 0/81.5 - not counting I-15 overlap
I-215: 25.2/29

So all told, 170.6/938 = 18%. Not bad for a state with a lot of rural mileage.