Widest section of freeway in your area

[doorknob60]

Boise (and Idaho) would be I-84 between I-184 and Cole/Overland Rd interchanges. 6 lanes eastbound and 5 lanes westbound (11 total):


As for the most lanes on one carriageway, just west of that there's 7 eastbound lanes (but only 3 westbound):


Street view of that part:

[bzakharin]

NJ Turnpike also has a section with 14 lanes. If you want to count the transition point between Car/Truck setup and Eastern/Western spur, there are briefly 16+ lanes there. And of course the Driscoll Bridge of the Garden State Parkway, with 15 lanes (+6 shoulders), is the widest bridge in the world.

[US 89]

NJ Turnpike also has a section with 14 lanes. If you want to count the transition point between Car/Truck setup and Eastern/Western spur, there are briefly 16+ lanes there. And of course the Driscoll Bridge of the Garden State Parkway, with 15 lanes (+6 shoulders), is the widest bridge in the world.

And that doesn't even include the US 9 bridges. If you include those, the entire complex has 21 lanes.

[Brandon]

And a little Google Street View of each.

For a single freeway: Dan Ryan (I-90/94), 17 lanes. 3 locals, 4 express

From Root Street, looking north.

For multiple freeways: I-355/I-88 side by side, 16 lanes at the widest point. I-88 has 5 eastbound, 4 west. I-355 has 3 northbound, 4 south.

From Finley Road, looking east.

[oscar]

Let's not forget the I-5/I-405 junction in Orange County CA, near where I once lived. I-5 momentarily bloats out to 26 lanes, divided among six carriageways for mainline, HOV, and truck lanes in both directions.

[roadman65]

I-4 was the widest in Orlando between Colonial and Ivanhoe, but the I-4 ultimate has that narrowed.  Though when completed the new I-4 will have 16 lanes overall, plus some sections when the beyond the ultimate project is built with even more as there will be some areas with c/d roadways in addition to the extended HOT lanes.

[triplemultiplex]

Madison
2-3-3-2 on "The Interstate" at US 151.
The c/d carriageways make it that wide.

Beyond that, The Interstate is briefly 9 lanes wide (4-5) on the north end of the Badger Interchange.

[cpzilliacus]

Maryland:

I-95/I-495 at the Woodrow Wilson Bridge (to Alexandria, Virginia) is 10 lanes, with two additional lanes not currently used.

I-95 in the Laurel and Beltsville area of Prince George's County (near MD-200) is 14 lanes across 4 roadways.

I-270 in Rockville, Montgomery County (between Montrose Road and MD-189) is 12 lanes across 4 roadways.

[roadfro]

In Nevada, the current widest is probably I-15 in Las Vegas, just north of I-215. With the movements to/from the 215 and the parallel C/D roads, the configuration is 2+6+6+2 (the "6" are comprised of 1 auxiliary lane, 3 general purpose through lanes, and 2 express through lanes).

This is likely to change with I-15 Project Neon, as the width of freeway will be dramatically widened just south of US 95, with southbound C/D road and new HOV lanes.

There are a couple spots between the Reno airport and I-80 where northbound I-580/US 395 bloats up to 7 lanes.  Southbound has 4 through lanes in that area and sometimes an exit-only lane.  I'm not sure it ever gets up to 12 lanes; it might max out at either 7 + 4 or 6 + 5.

It maxes out at 6 through lanes northbound and 4 through lanes southbound, with both directions having auxiliary lanes at some points but not usually at the same time. The point where it gets closest 12 total lanes only counts depending on how you look at it. Southbound, at the Mill St exit is 4 through lanes plus the lane drop to Mill St–directly opposite that point northbound is the off ramp to E Second/Glendale, with six through lanes and the option & lane drop already starting to diverge to the off ramp.

[GaryV]

Where I-696 is "inside" M-10 for about a mile at the US-24 "Mixing bowl" interchange, I counted 19 lanes including some exit and merge lanes.

https://www.google.com/maps/@42.4873745,-83.2787835,1220m/data=!3m1!1e3?hl=en

[fillup420]

Charleston, SC

I-26 at the interchange with Ashley Phosphate Rd and US 52/78. Twelve lanes across.

[Eth]

Whether this really counts as a single freeway is debatable, but at this location just southwest of the Atlanta airport I count a total of twenty-two (22) lanes strewn across six carriageways. From north to south:

• C/D lanes from I-85 south/I-285 west (4)
  
• I-285 westbound (4)
  
• I-85 southbound (4)
  
• I-85 northbound (3)
  
• I-285 eastbound (3)
  
• C/D lanes from I-85 south/I-285 south/GA 14 Conn east (4)
  

[Flint1979]

In my area I-75 is eight lanes between Saginaw and Flint. There isn't anything wider than that around here.