Charlotte

[jdunlop]

You are a good person to ask and perhaps <Rothman> as well.  Several years ago upthread, I asked whether anyone knew of whether the FHWA still requires the construction of HOV/HOT lanes when a full-blown widening is justified in situations like in South Charlotte.  (Those rules were in place back in the late 1990s and were VERY useful for us when we compared the costs of proposed transit projects with the costs of comparable highway projects).  Any idea if Federal funding still forces HOV/HOT, or if indeed the MPO has to push for such restrictions?

I was in our signals unit in the '90s, so not directly involved in the TIP projects other than designing the signals that were (a small) part of the project.  So wasn't aware that FHWA "forced" HOV lanes (don't believe HOT lanes were really a thing then, certainly not in NC.)  And I don't recall that it was a thing once I was involved on the traffic analysis side of them from late 1999-on.  I think it was a separate funding source for HOVs (I was never very involved in funding, so don't know much detail in that area.)

I do recall that in the early 2000s (don't recall the exact year) NC had no HOV lanes. The then secretary (Lyndo Tippett) wanted to have them somewhere in NC.  I was asked to come up with a location.  At the time, I-77 north of 85 was slated to be widened.  (Don't recall exactly how far north, 85 to Huntersville perhaps?  This project predated 485 in the area.) Our analysis based on the volume projections showed that the fourth lane was "extra" capacity, and that marking it as an HOV lane would be OK.  So that's how HOV lanes first appeared in NC.

A couple of things.  First, our forecasting group REALLY underestimated the growth in the area!   

Second, the meeting actually was about "thru lanes", as in designating inside lanes as exclusive through lanes, sort of like express/local lanes.  I recall mentioning the I-80 setup in Bergen County NJ (separate roadways though) and unofficial lane designations in Richmond where I-64 merged into I-95 (they relatively recently (a couple of years ago) dropped SB 95 to two lanes to give the merging 64 traffic an exclusive lane.)  Basically a "heavy merge ahead" situation.

Lastly, those HOV lanes (one N one S) were the basis of the toll lanes that eventually went in, one of the two lanes now used as such.  I do recall that a purposely built HOV lane could not be converted to a regular lane if funded by FHWA specifically as such, but since these were not (just designated as HOV) that rule didn't apply.

Regarding HOV/HOT "helping" capacity, I do recall one simulation we did that showed that the weaving traffic from the HOT lane on (I think 77) hurt the general lanes' capacity/operation due to the lane shifting/weaving the HOT vehicles had to do to get to their exit.  I think this was resolved by lengthening the weaving section (moving the HOT exit area further upstream from the target exit.)

[Rothman]

All I can say is my transportation-related career started later than the late 1990s, so I don't remember HOT/HOV lanes being mandated, but that doesn't mean they weren't.  Certainly aren't now.

[Dirt Roads]

Just for the record, the FHWA was requiring a specific level of environmental improvement with respect to the emissions calculations for added lanes.  In a few cases (say widening before level-of-service got too bad, it may have been possible to add lanes such that the resulting emissions were indeed lower after the project.

[Rothman]

Just for the record, the FHWA was requiring a specific level of environmental improvement with respect to the emissions calculations for added lanes.  In a few cases (say widening before level-of-service got too bad, it may have been possible to add lanes such that the resulting emissions were indeed lower after the project.

Yep, this broader requirement is what I've known.

[architect77]

I contacted NCDOT and the Turnpike Authority about lowering the I-77 initial toll rates to encourage more use of the lanes. The project's purpose was to add capacity to I-77, and that is only realized when the lanes are substantially utilized on a daily basis.

I shared my understanding of the sole purpose of Express Lanes which is to offer the option for everyone at times when they need it, a 45mph or faster free flowing lane for a price that offers a predictable travel time for set distance.

I also cited Atlanta's initial toll rates of 50 cents for several miles long sections and increasing them as the lanes fill up to capacity each rush period. The lanes would be more beneficial to all parties when heavily used at lower toll rates until full.

Here is their response and I'm happy that they shared my suggestion to the group that sets the pricing:

Hi Stephen,

The I-77 Express Lanes are part of a public-private partnership between NCDOT and I-77 Mobility Partners. We have shared your feedback with I-77 Mobility Partners. While NCDOT doesn't set the toll rates, we want to ensure the express lanes are performing as required in the contract and by federal requirements. Since the original contract was signed in 2014, NCDOT has negotiated several key improvements to toll rate transparency, expanded use of the lanes and uniform customer experience. NCDOT will continue to seek opportunities to improve the contract to ensure the best possible experience for all travelers who use the corridor.

We don't want drivers to pay more than they have to — we recommend drivers sign up for an NC Quick Pass account to save 50% on all tolls in North Carolina at ncquickpass.com. NC Quick Pass customers can also travel free in the express lanes with three or more people in the car, a transponder and set HOV status.

So does the NCQuickpass give people a 50% discount on the Express Lane toll prices? I know that is true for the bill by mail price on the other tolled roads statewide.

I also didn't realize that 3 occupants using NCQuickPass can use the Express Lanes for free on I-77.

[Dirt Roads]

Just for the record, the FHWA was requiring a specific level of environmental improvement with respect to the emissions calculations for added lanes.  In a few cases (say widening before level-of-service got too bad, it may have been possible to add lanes such that the resulting emissions were indeed lower after the project.

Yep, this broader requirement is what I've known.

We transit guys didn't consider that to be a "broad requirement".  If you couldn't prove that you could bring down emissions by adding extra lanes, you had to restrict the extra lanes to minimize the additional traffic.  If even a small section has an "adverse environmental impact" due to additional emissions, the FHWA does require mitigation [by either HOV or HOT] and as a corollary, the entire corridor gets hit.  It was an easy trick for the transit guys to walk into the room and say "I-40 needs an additional 4000 peak VPHPD in the rush hour and they can't get that capacity with two new HOV lanes" (which was sometimes was more expensive than the transit option; sometimes not).

It seems weird that CRTPO would openly announce the preference of HOT over free lanes.  The HOT experiment in Charlotte has been very unpopular with the masses (not quite as bad on the I-485 side near Ballantyne).  But historically, the benefit of HOT was the immediate impact of additional construction bonds to get the project under construction sooner than if you wait for traditional funding sources. 

[architect77]

Just for the record, the FHWA was requiring a specific level of environmental improvement with respect to the emissions calculations for added lanes.  In a few cases (say widening before level-of-service got too bad, it may have been possible to add lanes such that the resulting emissions were indeed lower after the project.

Yep, this broader requirement is what I've known.

We transit guys didn't consider that to be a "broad requirement".  If you couldn't prove that you could bring down emissions by adding extra lanes, you had to restrict the extra lanes to minimize the additional traffic.  If even a small section has an "adverse environmental impact" due to additional emissions, the FHWA does require mitigation [by either HOV or HOT] and as a corollary, the entire corridor gets hit.  It was an easy trick for the transit guys to walk into the room and say "I-40 needs an additional 4000 peak VPHPD in the rush hour and they can't get that capacity with two new HOV lanes" (which was sometimes was more expensive than the transit option; sometimes not).

It seems weird that CRTPO would openly announce the preference of HOT over free lanes.  The HOT experiment in Charlotte has been very unpopular with the masses (not quite as bad on the I-485 side near Ballantyne).  But historically, the benefit of HOT was the immediate impact of additional construction bonds to get the project under construction sooner than if you wait for traditional funding sources.

I don't know what year all of this is referring to, but emissions for new cars drastically decreased over the last 20 years. My 2011 car is SULEV which I believe is the type that greatly reduced impact on air quality and is one of the reasons LA went from always smoggy in the 90s to today where the San Gabriel mountains are always visible now unlike in the 90s when only on the day after it rained could you see them at all.

They say that one lawnmower engine now emits the same as 20 new passenger cars. Does anyone know if this ended restrictions on adding general purpose lanes? It would make sense if that was the case.

As I understand it today there are no HOT lanes in NC only Express Lanes which are different. Express Lanes offer a free flowing lane at 45mph or faster and are regulated to maintain that minimum speed.

HOT lanes as I understand them are paying for single occupant vehicles to use HOV lanes. The flow is not regulated via dynamic pricing in an HOV lanes or HOT lane. It's just a set price for a certain distance.

I support mass transit, however I don't agree that it's an equal alternative to vehicle lanes because transit only serve people and 50% or more of all highway usage is transporting food, products and materials.

Lanes are universally beneficial for all commerce and for meeting the needs of an entire population. They also are user-funded with a little supplement from general tax revenue, and transit requires 75% of its annual operating costs to be funded by all local citizens' paying extra sales taxes whether they use it or not. It works out to be about $300 per citizen per year if paying 1.5% extra sales taxes on every purchase.

[Dirt Roads]

Just for the record, the FHWA was requiring a specific level of environmental improvement with respect to the emissions calculations for added lanes.  In a few cases (say widening before level-of-service got too bad, it may have been possible to add lanes such that the resulting emissions were indeed lower after the project.

Yep, this broader requirement is what I've known.

We transit guys didn't consider that to be a "broad requirement".  If you couldn't prove that you could bring down emissions by adding extra lanes, you had to restrict the extra lanes to minimize the additional traffic.  If even a small section has an "adverse environmental impact" due to additional emissions, the FHWA does require mitigation [by either HOV or HOT] and as a corollary, the entire corridor gets hit.  It was an easy trick for the transit guys to walk into the room and say "I-40 needs an additional 4000 peak VPHPD in the rush hour and they can't get that capacity with two new HOV lanes" (which was sometimes was more expensive than the transit option; sometimes not).

It seems weird that CRTPO would openly announce the preference of HOT over free lanes.  The HOT experiment in Charlotte has been very unpopular with the masses (not quite as bad on the I-485 side near Ballantyne).  But historically, the benefit of HOT was the immediate impact of additional construction bonds to get the project under construction sooner than if you wait for traditional funding sources.

I don't know what year all of this is referring to, but emissions for new cars drastically decreased over the last 20 years. My 2011 car is SULEV which I believe is the type that greatly reduced impact on air quality and is one of the reasons LA went from always smoggy in the 90s to today where the San Gabriel mountains are always visible now unlike in the 90s when only on the day after it rained could you see them at all.

They say that one lawnmower engine now emits the same as 20 new passenger cars. Does anyone know if this ended restrictions on adding general purpose lanes? It would make sense if that was the case.

I've certainly been wondering the same thing.  Here in Orange County NC, the high rate of adoption of newer cars allowed us to eliminate the need for emissions testing altogether, even with a 15% growth since 2010.  All of the only counties in the area are still required to have emission testing every other year.

As I understand it today there are no HOT lanes in NC only Express Lanes which are different. Express Lanes offer a free flowing lane at 45mph or faster and are regulated to maintain that minimum speed.

HOT lanes as I understand them are paying for single occupant vehicles to use HOV lanes. The flow is not regulated via dynamic pricing in an HOV lanes or HOT lane. It's just a set price for a certain distance.

Somebody correct me, but your definition of Express Lane seems to be the same as the I-495 HOT Lanes and I-66 HOT in Northern Virginia.

[Dirt Roads]

I support mass transit, however I don't agree that it's an equal alternative to vehicle lanes because transit only serve people and 50% or more of all highway usage is transporting food, products and materials.

Lanes are universally beneficial for all commerce and for meeting the needs of an entire population. They also are user-funded with a little supplement from general tax revenue, and transit requires 75% of its annual operating costs to be funded by all local citizens' paying extra sales taxes whether they use it or not. It works out to be about $300 per citizen per year if paying 1.5% extra sales taxes on every purchase.

There is always a misunderstanding that a rail transit is somehow competing* against local highway funding (and even I would like to think so).  But local highway projects are competing against other highway projects for rankings in their state's STIP.  And local rail transit project are competing against other large transit projects across the nation.

What is important here is that the Federal Transit Administration requires a robust Alternatives Analysis, which almost always pits the preferred rail technology against less expensive forms of rail transit and bus rapid transit along the same corridor.  The AA also pits the preferred rail technology against both (A) upgrades to the existing traditional bus transit system to accommodate the same numbers of peak passengers; and (B) upgrades to the existing highway infrastructure to accommodate the same numbers of peak car passengers with the appropriate increase to peak VPHPD (back in my days, we were only assuming 1.2 passengers per car on average).  On most transit planning efforts, something other than rail transit wins the Alternative Analysis and the project is shelved.

Local transportation planners sometimes get thrown for a loop when a [marginal] rail transit project actually makes it through the AA selection process.  There's a perception that such a rail transit project (which is projected to pull a certain small percentage of passengers out of cars) eliminated the need for additional lanes on a parallel freeway or arterial.  And sometimes we see DOTs that yank a deserving highway widening project out of the STIP, when in reality, our construction would necessitate higher roadway capacities in the surrounding areas. 

* For the record, most states and local jurisdictions do encounter funding issues if parallel routes are under construction during the same/similar timeframes.  So in that sense, rail transit and highway can be in competition for a certain amount of funding.  Charlotte may be facing that right now with parallel needs to widen the I-77 North HOT lanes while at the same time pull off a New Start with the parallel Red Line Commuter Rail system.

I support mass transit, however I don't agree that it's an equal alternative to vehicle lanes because transit only serve people and 50% or more of all highway usage is transporting food, products and materials. Lanes are universally beneficial for all commerce and for meeting the needs of an entire population.

I used to agree with you here.  But with the advent of the emissions calculations used for highway widening alternatives (making it nearly impossible to avoid HOV lanes), it became obvious in the mid-1990s that the added lanes did not improve the transport of goods and materials except in the off-peak hours.  Most huge cities now have heavy traffic for 10 or more hours in each direction (overlapped in midday) such that the only free flow periods are midnights and weekends.  If the MPO didn't want HOV lanes, it would take so long to qualify for a lane widening project that the additional lanes were already choked before they were constructed.  Fortunately, neither Charlotte nor Raleigh/Durham are that big yet.  But Atlanta certainly is.

On the other hand, it is not appropriate to assume that a parallel rail transit system will reduce the demand for a freeway into the core of a huge city.  But the Southeast Florida experiment (known as Tri-Rail) did prove that a parallel rail corridor can assist with the total reconstruction of an old freeway corridor.  Seems that nobody got the memo yet.

[architect77]

I support mass transit, however I don't agree that it's an equal alternative to vehicle lanes because transit only serve people and 50% or more of all highway usage is transporting food, products and materials.

Lanes are universally beneficial for all commerce and for meeting the needs of an entire population. They also are user-funded with a little supplement from general tax revenue, and transit requires 75% of its annual operating costs to be funded by all local citizens' paying extra sales taxes whether they use it or not. It works out to be about $300 per citizen per year if paying 1.5% extra sales taxes on every purchase.

There is always a misunderstanding that a rail transit is somehow competing* against local highway funding (and even I would like to think so).  But local highway projects are competing against other highway projects for rankings in their state's STIP.  And local rail transit project are competing against other large transit projects across the nation.

What is important here is that the Federal Transit Administration requires a robust Alternatives Analysis, which almost always pits the preferred rail technology against less expensive forms of rail transit and bus rapid transit along the same corridor.  The AA also pits the preferred rail technology against both (A) upgrades to the existing traditional bus transit system to accommodate the same numbers of peak passengers; and (B) upgrades to the existing highway infrastructure to accommodate the same numbers of peak car passengers with the appropriate increase to peak VPHPD (back in my days, we were only assuming 1.2 passengers per car on average).  On most transit planning efforts, something other than rail transit wins the Alternative Analysis and the project is shelved.

Local transportation planners sometimes get thrown for a loop when a [marginal] rail transit project actually makes it through the AA selection process.  There's a perception that such a rail transit project (which is projected to pull a certain small percentage of passengers out of cars) eliminated the need for additional lanes on a parallel freeway or arterial.  And sometimes we see DOTs that yank a deserving highway widening project out of the STIP, when in reality, our construction would necessitate higher roadway capacities in the surrounding areas. 

* For the record, most states and local jurisdictions do encounter funding issues if parallel routes are under construction during the same/similar timeframes.  So in that sense, rail transit and highway can be in competition for a certain amount of funding.  Charlotte may be facing that right now with parallel needs to widen the I-77 North HOT lanes while at the same time pull off a New Start with the parallel Red Line Commuter Rail system.

I support mass transit, however I don't agree that it's an equal alternative to vehicle lanes because transit only serve people and 50% or more of all highway usage is transporting food, products and materials. Lanes are universally beneficial for all commerce and for meeting the needs of an entire population.

I used to agree with you here.  But with the advent of the emissions calculations used for highway widening alternatives (making it nearly impossible to avoid HOV lanes), it became obvious in the mid-1990s that the added lanes did not improve the transport of goods and materials except in the off-peak hours.  Most huge cities now have heavy traffic for 10 or more hours in each direction (overlapped in midday) such that the only free flow periods are midnights and weekends.  If the MPO didn't want HOV lanes, it would take so long to qualify for a lane widening project that the additional lanes were already choked before they were constructed.  Fortunately, neither Charlotte nor Raleigh/Durham are that big yet.  But Atlanta certainly is.

On the other hand, it is not appropriate to assume that a parallel rail transit system will reduce the demand for a freeway into the core of a huge city.  But the Southeast Florida experiment (known as Tri-Rail) did prove that a parallel rail corridor can assist with the total reconstruction of an old freeway corridor.  Seems that nobody got the memo yet.

I'm glad Charlotte owns the track for the commuter line alongside I-77. The city center hosts enough jobs that it should be a success. Yes you can apply for federal help for construction costs like with the next LRT line. The operating costs each year afterwards is over time probably the bigger expense that the feds won't pay for.

But NC's successful intrastate service through central NC is a winner and should be enhanced with additional lines which is likely.

But I-77 can't receive major state funding for a long while after the region got so much from 2010-2023 with the 8-lane I-85 and the concrete pavement and deluxe North and Western I-485 projects. Even with the scoring which it a good new system, other areas of the state wait and take turns for major funding. Construction costs since 2018 are up 70% and the Raleigh area has had 9 projects delayed until 2031-2035 even US1 North of Raleigh which is so urgent. Charlotte is getting another lane on I-85 to Gastonia already underway, and the area has the biggest and nicest freeways in the state. Lucky you.

I am all for Express Lanes as they operate in Atlanta because you can keep them free-flowing forever into the future with dynamic pricing.

But as of now Cintra is not operating the North I-77 lanes appropriately to serve the intended purpose with such egregious base toll rates. I cannot believe anyone in Charlotte or NCDOT would even consider entering another agreement with them based on the feelings of the $5 for 2 miles overcharging with a $40 total or so for the entire length of the lanes.

I wasn't even commenting on whether free or new tolled lanes should be added. I just wanted to make the point that mass transit and highways are not equal in terms of universal use and benefit. Highways accommodate every business and 70% of all US freight. Mass transit moves people only for a relatively high cost of ~ $14 per ride and fare revenue covers 1/4 of the total operating expenses, and additional sales taxes on every purchase covers the other 3/4. I have to be honest that Atlanta''s 8.9% sale tax is a burden, and for every $1000 purchase it's almost $100 in sales tax so it's substantial. Day after day small purchases have you paying  $5 here $7 dollars there in sales tax. It sucks. Mecklenburg residents are just beginning to feel what 8.25% sales tax now?

50% of all traffic is transporting goods, and growing regions require keeping capacity commensurate with the increased population needing food, materials, fuel, etc.

I still want to find out if the air quality based restrictions on additional highway construction is still active now that cars are cleaner.

I've read about Atlanta's federal restrictions since the 1990s about building additional highways. It must be the stagnant Southeast air at various times a year that mandated several NC counties and metro Atlanta to need annual emissions tests. But I read 2 years ago that NC counties no longer needed them anymore despite the growth and I think the state stopped requiring them. I know that Mecklenburg Co. barely missed meeting the threshold at that time so testing continued for another year.

As far as the hours per day that freeways flow freely, I think there are a whole lot of factors that play into that, like when you compare the extensive freeway connectivity in Dallas compared to Atlanta which didn't expanded its footprint at all really from the original 1960s layout.

Metro Atlanta as a result forces 1/4 of the population to use just one trunk interstate in each cardinal direction to traverse the region and 1 fender bender can make 200,000 people late for work. It's  not ideal but Georgia is not a prolific road building state like NC has always been.

[Rothman]

Come to think of it, NY's attainment area/CMAQ eligibility shrank considerably when feds reassessed it a decade ago or so.  Only Upstate area eligible now is Chautauqua County (thanks, Ohio).

So, I'd imagine other eligibilities may have changed accordingly.

[Dirt Roads]

But I-77 can't receive major state funding for a long while after the region got so much from 2010-2023 with the 8-lane I-85 and the concrete pavement and deluxe North and Western I-485 projects. Even with the scoring which it a good new system, other areas of the state wait and take turns for major funding. Construction costs since 2018 are up 70% and the Raleigh area has had 9 projects delayed until 2031-2035 even US1 North of Raleigh which is so urgent. Charlotte is getting another lane on I-85 to Gastonia already underway, and the area has the biggest and nicest freeways in the state. Lucky you.

That used to be true when our STIP was a strictly statewide programme and NCDOT was attempting to balance the funding between urban and rural corridors.  But now we have a tiered-STIP programme that funds one set of statewide priority corridors (40%); funds other corridors on a regional priority basis (30%); and also as well as other highway needs on a district priority basis (30%).  (Although I worded this the way that the STIP is supposed to work, my understanding is that an Interstate project that missed getting funding on the statewide priority list actually could get funded on the regional or district priority lists, but certainly at the risk of reducing the total numbers of projects that could receive funding if the Interstate project is huge and expensive).

I still want to find out if the air quality based restrictions on additional highway construction is still active now that cars are cleaner.

I've read about Atlanta's federal restrictions since the 1990s about building additional highways. It must be the stagnant Southeast air at various times a year that mandated several NC counties and metro Atlanta to need annual emissions tests. But I read 2 years ago that NC counties no longer needed them anymore despite the growth and I think the state stopped requiring them. I know that Mecklenburg Co. barely missed meeting the threshold at that time so testing continued for another year.

At least for now, NCDMV still requires emission testing in 19 counties.  In addition to a wide swath across the I-85 Corridor (plus Raleigh), it still includes the counties surrounding Asheville, Fayetteville and Wilmington.  I should also mention that Orange County has been the only missing piece in the swath.

With respect to your question about how the FHWA Environmental Review process affects the construction of additional lanes, it is my impression that emphasis on the term "stewardship" pushes more of the decision making responsibility onto the states and their regional MPOs.  That should help the process, since the primary goal (irrespective of any political viewpoint) is to avoid rush hour situations whereby all vehicles operate at stop-and-go (LOS Level F) for several hours at a time.

[Dirt Roads]

At least for now, NCDMV still requires emission testing in 19 counties.  In addition to a wide swath across the I-85 Corridor (plus Raleigh), it still includes the counties surrounding Asheville, Fayetteville and Wilmington.  I should also mention that Orange County has been the only missing piece in the swath.

Those 19 counties account for just over 60% of North Carolina's population.  I was suspecting a number much higher.

[Rothman]

"Programme"?

*raises eyebrow*

[jdunlop]

That used to be true when our STIP was a strictly statewide programme and NCDOT was attempting to balance the funding between urban and rural corridors.  But now we have a tiered-STIP programme that funds one set of statewide priority corridors (40%); funds other corridors on a regional priority basis (30%); and also as well as other highway needs on a district priority basis (30%).  (Although I worded this the way that the STIP is supposed to work, my understanding is that an Interstate project that missed getting funding on the statewide priority list actually could get funded on the regional or district priority lists, but certainly at the risk of reducing the total numbers of projects that could receive funding if the Interstate project is huge and expensive).

Yes, that's how the tiers work.  If a project doesn't get funded at the statewide level, it can drop to either the regional (made up of two divisions) or division levels.  (NCDOT is divided into 14 Divisions, which are then divided into (mostly) 3 districts per Division.  Other states, such as Florida call the larger area a District.)  The funding for statewide projects is 100% data driven, while the other two tiers (equal money per region/division) are 70/30 data/local input and 50/50. 

It would be rare (IIRC) that a statewide project gets funded in lower tiers, especially in urban areas.  They typically have other priorities.  It doesn't happen too often at the Division level either.

There is a "corridor cap" that limits the amount of money that can be spent on one "segment" of road during a certain period of time.  Those definitions have changed a bit since I was involved, so I can't tell you what those limits are.  The toll roads are subject to that cap, but I believe the toll revenue spent on a project is not included in the cap calculations.

[architect77]

That used to be true when our STIP was a strictly statewide programme and NCDOT was attempting to balance the funding between urban and rural corridors.  But now we have a tiered-STIP programme that funds one set of statewide priority corridors (40%); funds other corridors on a regional priority basis (30%); and also as well as other highway needs on a district priority basis (30%).  (Although I worded this the way that the STIP is supposed to work, my understanding is that an Interstate project that missed getting funding on the statewide priority list actually could get funded on the regional or district priority lists, but certainly at the risk of reducing the total numbers of projects that could receive funding if the Interstate project is huge and expensive).

Yes, that's how the tiers work.  If a project doesn't get funded at the statewide level, it can drop to either the regional (made up of two divisions) or division levels.  (NCDOT is divided into 14 Divisions, which are then divided into (mostly) 3 districts per Division.  Other states, such as Florida call the larger area a District.)  The funding for statewide projects is 100% data driven, while the other two tiers (equal money per region/division) are 70/30 data/local input and 50/50. 

It would be rare (IIRC) that a statewide project gets funded in lower tiers, especially in urban areas.  They typically have other priorities.  It doesn't happen too often at the Division level either.

There is a "corridor cap" that limits the amount of money that can be spent on one "segment" of road during a certain period of time.  Those definitions have changed a bit since I was involved, so I can't tell you what those limits are.  The toll roads are subject to that cap, but I believe the toll revenue spent on a project is not included in the cap calculations.

Charlotte is lucky that it straddles 2 highway divisions, as both probably prioritize the most populous region in their districts.

The entire Triangle area falls in a single division. I remember a citizen from Franklin Co. who went to all the DOT meetings comment on how difficult it was for a rural county to get any improvement projects funded when competing with Wake and Durham Counties for attention.