Six or more lane highways that could work as four laners

[ftballfan]

I-65 in KY.  I-75 in GA.  I-95 in FL.

As somebody with personal experience on I-75 in Georgia, that absolutely needs its six lanes.

No question I-75 needs to be six lanes in Georgia. Heck in some areas it could even be eight lanes.

During any sort of holiday/vacation travel period I-65 is packed, if anything it needs the 6 lane extended into IN and TN (which has recently begun in both states). I-75 needs to be 6 lanes for hurricane evacuation as well as normal traffic days. I don't have as much experience on I-95 but I would imagine in FL it would follow the same justification as I-75.

The last time I was on I-65 in Indiana in mid-March, they were 6-laning parts of it between Indy and Louisville (which it needed years ago).

[jeffandnicole]

I-65 in KY.  I-75 in GA.  I-95 in FL.

As somebody with personal experience on I-75 in Georgia, that absolutely needs its six lanes.

No question I-75 needs to be six lanes in Georgia. Heck in some areas it could even be eight lanes.

No one is disputing that it needs at least six lanes from the Tennessee line to at least Macon.
Once you get south of Macon, however, four lanes could work, at least in the sense that many other roads nationwide with similar volumes (the Thruway in NY, parts of I-81 and I-78 in PA, etc.) have just four lanes and are not being seriously considered for widening.

If the question is "Should I-75 in Georgia should be reduced to four lanes?", then the answer is definitely No.
If the question is "Would I-75 south of Macon function reasonably well with four lanes?" the answer is probably Yes.

Would you also be in favor of reducing the speed limit to 65 mph on a 4 lane I-75 in Georgia? If you're comparing volumes to a 4 lane 78/81 in PA/NY, you would need to compare the speed limit as well.

I think the issue here is that I-78 has very substandard geometry in places, and anyways, much of I-81 should most definitely be 70, even with existing traffic volumes. I-75 in Georgia is not saddled with poor geometry or a low-speed-limit DOT in the same way.

Traffic volumes are a consideration as well when it comes to speed limits.

If you're taking the volume of traffic on a 6 lane roadway, and pushing that volume of traffic on a 4 lane roadway, it absolutely has a significant effect on what the speed limit should be.

A more appropriate comparison would be an in-state comparison.  Do the traffic volumes on the 4 lane sections of I-20 in GA compare similarly to the 6 lane sections of I-75 in GA?  If there's more traffic on I-75, would the thresholds that permit 70 mph on a 6 lane roadway remain true if it was to be narrowed to a 4 lane I-75?

It is also a bit funny that there's a comparison to 2 other highways because they have similar traffic volumes (citation needed), but once the speed limit was brought into the equation, suddenly the comparison isn't comparable.

[Big John]

The speed limit is supposed be the 85th prevailing percentile of traffic speed (rounded to the x5 or x0).  But the reality is the local speed limit are usually lower to extremely lower and  they use law enforcement to lower the speed to the low number.

[webny99]

It is also a bit funny that there's a comparison to 2 other highways because they have similar traffic volumes (citation needed), but once the speed limit was brought into the equation, suddenly the comparison isn't comparable.

Guessing this is being addressed to me: I-78 in PA generally has an AADT of between 35K and 50K between I-81 and Allentown, and even higher east of there. I-81 in PA has volumes well above 40K from the Maryland line to Harrisburg, and the section north of Scranton is also very comparable. I checked several points for I-75 south of Macon, and they're generally in that range.

As for the point about the comparison no longer being comparable, I'm not arguing that at all. I'm just saying that whether or not a highway needs to be widened should be based on the volumes, while the speed limit should be set based on the overall design, geometry, etc.
In other words, if 40K is your established threshold for widening, then I-81 from the MD line to Harrisburg should be widened period. Whether the speed limit is 55 mph or 80 mph is a non-factor.

[Roadgeekteen]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

[hotdogPi]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

How hard is it to spell Myanmar?

[Flint1979]

The only one that "could" work is I-475 through Flint.

How would that work? I-475 is an alternate route for I-75 and gets around 60,000 VPD.

[Roadgeekteen]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

How hard is it to spell Myanmar?

Both are correct so I used the easier one to spell.

[Rothman]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

How hard is it to spell Myanmar?

Both are correct so I used the easier one to spell.

Myanmar is correct.  Burma is not.

[kphoger]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

How hard is it to spell Myanmar?

Both are correct so I used the easier one to spell.

Myanmar is correct.  Burma is not.

Depends who you ask.  Last I knew, the US government still officially refers to the nation as 'Burma'.  On purpose.

[Dirt Roads]

I think there are some super wide highways in Burma (easier to spell) and North Korea that get little use but I might be wrong.

How hard is it to spell Myanmar?

Both are correct so I used the easier one to spell.

Myanmar is correct.  Burma is not.

Depends who you ask.  Last I knew, the US government still officially refers to the nation as 'Burma'.  On purpose.

And sadly, a number of friends who are refugees from that county still say they are from Burma and are offended by the name Myanmar. 

[Flint1979]

I certainly think that I-75 between Dayton and Toledo is a strong contender for needing more than two lanes in each direction. I just spent the better part of 20 minutes about 10 mi North of tipp City fighting with semi truck after semi truck after semi truck it's ridiculous how much the semi trucks clog up the interstate highway system

[Flint1979]

And here's a prime example of my previous post. I have an SUV in front of me with a row semi trucks in the right lane the SUV is doing the same speed as the semi trucks. And there's nothing in front of the SUV a semi truck just hopped in front of the SUV now we're doing 62 mph. don't tell me that any part of I-75 between Michigan and Florida needs anything under three lanes in each direction.