Road diets / closures you're pretty okay with

[Road Hog]

Yes, I consider undivided four lane roads to be obsolete.

Especially from a safety standpoint, i.e. head-on collision risk.

On roads that have a freeway/expressway parallel, I'd agree.  Otherwise, capacity drops considerably when you consider that there is no longer any legal way to get around slow moving vehicles.

I wouldn't go so far as to say undivided four-lane roads are obsolete. In most cases, if four lanes are warranted, then a TWLTL is also warranted. But four lanes undivided does have limited utility in some cases, such as this stretch of NY 404, or this stretch of RR 57/Thorold Stone Rd in Ontario. In essence, it's probably warranted if all three of the following apply:

• Volumes are too much for two lanes to handle
• Side streets/businesses/driveways exist but are intermittent and not too closely spaced, so it's not worth creating a TWLTL
• Traffic is localized enough that a divided highway requiring U-turn movements is unnecessary/impractical

(That being said... one time I was on a four-lane road in heavy traffic I had a driver zoom up besides me  into the oncoming left lane to make a left turn, passing other left turners in the process and barely squeaking through the intersection before oncoming traffic arrived. He got a lengthy honk from me, one of the rare honking instances of "major safety hazard and major personal irritation". It did occur to me that this never would have happened on a three-lane road, or if it did, he would have at least been in the TWLTL instead of the oncoming lane.)

People in 49 states have a disparaging term for a highway with 5 lanes.

[jeffandnicole]

Yes, I consider undivided four lane roads to be obsolete.

Especially from a safety standpoint, i.e. head-on collision risk.

On roads that have a freeway/expressway parallel, I'd agree.  Otherwise, capacity drops considerably when you consider that there is no longer any legal way to get around slow moving vehicles.

I wouldn't go so far as to say undivided four-lane roads are obsolete. In most cases, if four lanes are warranted, then a TWLTL is also warranted. But four lanes undivided does have limited utility in some cases, such as this stretch of NY 404, or this stretch of RR 57/Thorold Stone Rd in Ontario. In essence, it's probably warranted if all three of the following apply:

• Volumes are too much for two lanes to handle
• Side streets/businesses/driveways exist but are intermittent and not too closely spaced, so it's not worth creating a TWLTL
• Traffic is localized enough that a divided highway requiring U-turn movements is unnecessary/impractical

(That being said... one time I was on a four-lane road in heavy traffic I had a driver zoom up besides me  into the oncoming left lane to make a left turn, passing other left turners in the process and barely squeaking through the intersection before oncoming traffic arrived. He got a lengthy honk from me, one of the rare honking instances of "major safety hazard and major personal irritation". It did occur to me that this never would have happened on a three-lane road, or if it did, he would have at least been in the TWLTL instead of the oncoming lane.)

People in 49 states have a disparaging term for a highway with 5 lanes.

Which is a misused term in these instances.  A TWLTL is not the same thing as an actual passing lane that can be used in either direction.