More or Fewer Interchanges?

[Ketchup99]

Different places adopt different attitudes towards whether freeways should have lots of interchanges or only a few. Toll roads generally have long distances between interchanges while free roads generally have them closer together, but with the dawn of AET there's no reason for that anymore. However, there are merits to both methods - which do you think should be generally used?

[kphoger]

with the dawn of AET there's no reason for that anymore

Please explain.

[sprjus4]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

[Ketchup99]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

This. I was also thinking of the "slip ramps" on the PA Turnpike that are being built for EZPass users.

[webny99]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

This. I was also thinking of the "slip ramps" on the PA Turnpike that are being built for EZPass users.

However, there's still a potential reason for fewer, more spread out interchanges on toll roads. It has been proven that fewer exits increases revenue. (This is something I have disagreed with in previous threads, and am still not entirely convinced of, but putting that aside for now...)

[Truvelo]

However, there's still a potential reason for fewer, more spread out interchanges on toll roads. It has been proven that fewer exits increases revenue. (This is something I have disagreed with in previous threads, and am still not entirely convinced of, but putting that aside for now...)

I assume this is because the minimum toll is higher if the interchanges are further apart. Those who 'junction hop' by leaving at the next interchange will pay more because they have to travel further. However I would have thought those doing such a thing would use a parallel free road than pay a toll for such a short distance.

[kphoger]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

But more interchanges still require the construction of more gantries, right?

[Ben114]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

But more interchanges still require the construction of more gantries, right?

It's cheaper than building a new toll plaza.

[kphoger]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

But more interchanges still require the construction of more gantries, right?

It's cheaper than building a new toll plaza.

Yes, but it's more than zero.  My disagreement was with the phrase "no reason".

[Ketchup99]

True, it's more than zero. But at this point, is it worth it for highways to have widely spaced interchanges?

[Joe The Dragon]

with the dawn of AET there's no reason for that anymore

Please explain.

AET allows interchanges to be placed more freely since it does not require construction of toll plazas, etc.

But more interchanges still require the construction of more gantries, right?

It's cheaper than building a new toll plaza.

I-490 is going to all AET and likely point based like the EOE

[hbelkins]

Keep in mind that on closed systems, keeping drivers on the toll road with fewer chances to exit means they're more likely to use gas stations and restaurants at service plazas instead of exiting to eat or fuel up off the turnpike.

However I would have thought those doing such a thing would use a parallel free road than pay a toll for such a short distance.

When I went to Breezewood for the abandoned PA Turnpike meet a few months ago, I went up US 219 from I-68. I was staying in Breezewood, but I didn't get on the turnpike at all. I took PA 31 and US 30 from Somerset to Breezewood.

We gathered in Bedford, so I did all my traveling between Breezewood and Bedford on US 30 instead of the turnpike. And I went home via US 220, so I used US 30 to reach that route when I departed. It might have been faster to use the turnpike, but I didn't want to pay the toll.

[Road Hog]

On freeways, one interchange per mile in urbanized areas is plenty. Works flipping fine on Central in Dallas and points north. Sherman doesn't need 12 exits and that's being fixed.

[STLmapboy]

Sherman doesn't need 12 exits and that's being fixed.

That seems like abuse of frontage roads, no? Similar story on rural I-44 between Wichita Falls and the Red River/OK line, having 16 exits in 15 miles.

[Hwy 61 Revisited]

On freeways, one interchange per mile in urbanized areas is plenty.

Tell that to the Alphabet Loop...

[cbeach40]

More accesses = more traffic generation (by spurring development), more traffic turbulence, and more infrastructure to maintain.
Fewer accesses = fewer locations for development so fewer vehicles on the road, smoother traffic flow*, less infrastructure to maintain

Basically, do you want to spur development with increased access, or do you want to improve highway throughput?


* - on the highway itself, on the adjacent street network they tend to be worse (all eggs in one basket sort of thing). That is until build out is substantial enough that everything is screwed. So that's more of a short-to-medium term advantage, long term it washes out.

And general disclaimer, the above applies whether the facility is toll or not. Toll just will throttle the demand so growth rates grow more slowly and trips are consolidated. But ultimately it's the same final result.

[roadman65]

I-295 & US 130 in Gloucester County, NJ has way too many as a result of a former US highway expressway alignment turned freeway.  Some could be dropped or consolidated.

I-95 from Eastover to Kenly in NC.  It has too many and many could be merged into another one mega interchange.  Although they are doing a consolidation in Dunn where Pope Road and US 421 will both be one interchange as a start, but more should be made.

[kphoger]

More accesses = more traffic generation (by spurring development), more traffic turbulence, and more infrastructure to maintain.
Fewer accesses = fewer locations for development so fewer vehicles on the road, smoother traffic flow*, less infrastructure to maintain

Basically, do you want to spur development with increased access, or do you want to improve highway throughput?

It's also a fundamental question of whether the freeway should also serve local traffic or not.  That is to say, should Old McDonald have easy access to the highway, considering it's right there by his farm, or should the freeway only really serve long-distance travelers.  Texas has historically gone by the first model, but other states haven't necessarily had the same m.o.

[Joe The Dragon]

More accesses = more traffic generation (by spurring development), more traffic turbulence, and more infrastructure to maintain.
Fewer accesses = fewer locations for development so fewer vehicles on the road, smoother traffic flow*, less infrastructure to maintain

Basically, do you want to spur development with increased access, or do you want to improve highway throughput?


* - on the highway itself, on the adjacent street network they tend to be worse (all eggs in one basket sort of thing). That is until build out is substantial enough that everything is screwed. So that's more of a short-to-medium term advantage, long term it washes out.

And general disclaimer, the above applies whether the facility is toll or not. Toll just will throttle the demand so growth rates grow more slowly and trips are consolidated. But ultimately it's the same final result.

and there is the local / express setups.
as well long frontages setups. 

[sparker]

More accesses = more traffic generation (by spurring development), more traffic turbulence, and more infrastructure to maintain.
Fewer accesses = fewer locations for development so fewer vehicles on the road, smoother traffic flow*, less infrastructure to maintain

Basically, do you want to spur development with increased access, or do you want to improve highway throughput?

It's also a fundamental question of whether the freeway should also serve local traffic or not.  That is to say, should Old McDonald have easy access to the highway, considering it's right there by his farm, or should the freeway only really serve long-distance travelers.  Texas has historically gone by the first model, but other states haven't necessarily had the same m.o.

Of course Texas developed the way to have one's cake and eat it too -- the continuous frontage road with slip-ramps to and from the freeway lanes.  Put as much local access as the market will bear on the frontage roads and make it easy for egress.  But to address the OP's main question -- it's likely that DOT's, faced with extending a new freeway outward from a beltway or bypass, will sniff the air around the origin point and determine if what if any interchanges would be optimal for the facility in question.  Ideally -- if development along the new corridor is to be avoided -- there will be a very long space between that origin interchange and the next access to a local road -- maybe as much as 5-6 miles.  The only problem is money-hungry jurisdictions in the vicinity of the new roadway who are stuck providing services to their ever-growing contingent of residents.  They need sales tax revenues, so they press for more and more interchanges at which to place tax-generating services.   Once that occurs, it tends to snowball; interchanges spaced a mile or less apart and frontage roads strung together along freeways old and new; it continues until there's no practical land remaining.  Freeways can be built in such a way as to avoid excessive adjacent development -- but that requires one hell of a lot of political will to resist the entreaties of developers and their allies.  That's only the beginning -- well past the inception of a new freeway, resisting the siren song of tax revenue has to be ongoing for the life of the facility. 

[cpzilliacus]

Different places adopt different attitudes towards whether freeways should have lots of interchanges or only a few. Toll roads generally have long distances between interchanges while free roads generally have them closer together, but with the dawn of AET there's no reason for that anymore. However, there are merits to both methods - which do you think should be generally used?

I-95 (Connecticut Turnpike - detolled in the 1980's), at least between the New York State border and New Haven, is a road that cries out for fewer access and egress points.

[sparker]

Different places adopt different attitudes towards whether freeways should have lots of interchanges or only a few. Toll roads generally have long distances between interchanges while free roads generally have them closer together, but with the dawn of AET there's no reason for that anymore. However, there are merits to both methods - which do you think should be generally used?

I-95 (Connecticut Turnpike - detolled in the 1980's), at least between the New York State border and New Haven, is a road that cries out for fewer access and egress points.

It's likely that when the CT Turnpike was being planned & developed in the early/mid 1950's, the highway department and/or toll authority were attempting to juggle the requirements of commuter traffic in the SW corner of the state (particularly as a number of those commuters had the clout to make very pointed phone calls to decision-makers) and through/commercial traffic then clogging US 1.  Providing frequent interchanges was probably a way to placate the Greenwich to Darien contingent (let 'em get on/off as close as they can to where they live) -- but likely at considerable expense, as toll collection facilities had to be installed at each of those.  These days, arguably most of those commuters have shifted to Metro-North simply to avoid the hassle (and $25-30/hour NYC parking garage rates!), so removing about a third to a half of the exits probably wouldn't draw a lot of flack.                 

[Hwy 61 Revisited]

Different places adopt different attitudes towards whether freeways should have lots of interchanges or only a few. Toll roads generally have long distances between interchanges while free roads generally have them closer together, but with the dawn of AET there's no reason for that anymore. However, there are merits to both methods - which do you think should be generally used?

I-95 (Connecticut Turnpike - detolled in the 1980's), at least between the New York State border and New Haven, is a road that cries out for fewer access and egress points.

It's likely that when the CT Turnpike was being planned & developed in the early/mid 1950's, the highway department and/or toll authority were attempting to juggle the requirements of commuter traffic in the SW corner of the state (particularly as a number of those commuters had the clout to make very pointed phone calls to decision-makers) and through/commercial traffic then clogging US 1.  Providing frequent interchanges was probably a way to placate the Greenwich to Darien contingent (let 'em get on/off as close as they can to where they live) -- but likely at considerable expense, as toll collection facilities had to be installed at each of those.  These days, arguably most of those commuters have shifted to Metro-North simply to avoid the hassle (and $25-30/hour NYC parking garage rates!), so removing about a third to a half of the exits probably wouldn't draw a lot of flack.                 

Shoulda followed 91 to Hartford.

[cpzilliacus]

Providing frequent interchanges was probably a way to placate the Greenwich to Darien contingent (let 'em get on/off as close as they can to where they live) -- but likely at considerable expense, as toll collection facilities had to be installed at each of those.

I drove the Connecticut Turnpike when it was still a toll road.  The Pike had barrier tolls not unlike the old days of the Garden State Parkway, where there was a toll barrier (both directions) every so often, and you dropped your quarter in the basket (though I believe there were always toll collectors on duty, as there were on the GSP). 

Unlike the turnpikes in Massachusetts, New York, New Jersey and Pennsylvania, there were no toll tickets, though I think the Connecticut Turnpike was long enough that a ticket system could have been justified (with fewer interchanges).

Nor did the Connecticut Turnpike have ramp tolls - at least I cannot remember ever seeing one.  But supposedly the barriers were positioned at or near town boundaries, so intra-town trips were generally free of tolls. 

[Roadgeekteen]

I think that the Mass Pike could use at least one more exit.