Crossing to Exit Ratios - More Exits or Less?

Started by webny99, March 06, 2018, 02:17:31 PM

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webny99

This is a concept I've given considerable thought to over the past few weeks as it relates to this discussion.
Which freeways have intersections with most or all cross streets, and which are lacking in this regard?

The two extreme examples are NY 104 and I-90 (the thruway). NY 104 crosses a total of 20 roads on its freeway segment east of Rochester. There is direct access to 16 of them, for a ratio of 4:5, or four exits for every five roads crossed. The Thruway, on the other hand, crosses 24 roads between (and including) exits 45 and 47. There's only three exits on this stretch, for a ratio of 1:8.

What other roads do you believe are extreme in this regard? What do you think is an ideal ratio, and how much higher should the ratio be in urban areas vs. rural areas?


jeffandnicole

Ratio probably isn't all that important.  If you have interchanges closer than 1.5 - 2 miles in urban areas, and 2.5 - 3 or more miles in suburban/rural areas, then you get too much weaving, entering and exiting traffic on the highway, which can jam it up.

There are exceptions.  On I-295 in NJ, in a 13 mile stretch of highway, there are an incredible 15 separate interchanges between Exits 13 & 25.  With one exception, Every Single Overpass has an interchange associated with it.

On the AC Expressway, Every single cross street has an exit between Exits 38 and 44.  But then again, there's only 3 cross streets - Exit 38, Exit 41 & Exit 44.  So not a big deal there.

froggie

Sounds like something for an aspiring statistical analyst to do some research on...

webny99

Quote from: jeffandnicole on March 06, 2018, 02:47:34 PM
Ratio probably isn't all that important.

That may be true, and I could have left ratios out of it. While the "unnecessary exits" thread linked above was meant for specific locations, the underlying question here is which freeways would flow better with less exits overall. And of course the reverse - which freeways have the fewest exits relative to crossings, and should more exits be added.

The ratio is simply a handy and easy-to-calculate piece of evidence you can use to support a claim that more or less exits are needed on a certain freeway segment - not something that should be read into too much.

Quote from: froggie on March 06, 2018, 08:14:02 PM
Sounds like something for an aspiring statistical analyst to do some research on...

I figured something along those lines was coming  :-D I think I've sufficiently defended myself above (to the extent that I needed defense).

hotdogPi

The Mass Pike could use more exits, maybe at most numbered routes instead of about every 10 miles, since there are no more physical toll booths. Exits would be renumbered to mileage-based.

I-95 in New Hampshire (tolled between Exit 1 and Exit 3) could also have more frequent exits, specifically one or both of NH 84 and NH 88, access to NH 27 via NH 101's exit, and standard interchanges with NH 111 and NH 151. There are still physical toll booths here, though.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

Rothman

Meh.  The only exit I can think of that would make sense for the Pike is at US 20 and MA 8, but AADT probably doesn't warrant it and I believe there has been local opposition to it.
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

jp the roadgeek

Quote from: Rothman on March 06, 2018, 09:15:15 PM
Meh.  The only exit I can think of that would make sense for the Pike is at US 20 and MA 8, but AADT probably doesn't warrant it and I believe there has been local opposition to it.

Could also put one at MA 19 or MA 67 in Warren.  There's a 15 mile gap between MA 32 in Palmer and I-84 in Sturbridge.  The US 20/MA 8 Exit makes sense for those of us driving up to Albany from areas west of Hartford who would rather use CT/MA 8 and not have to backtrack to I-91 to get to the Pike.
Interstates I've clinched: 97, 290 (MA), 291 (CT), 291 (MA), 293, 295 (DE-NJ-PA), 295 (RI-MA), 384, 391, 395 (CT-MA), 395 (MD), 495 (DE), 610 (LA), 684, 691, 695 (MD), 695 (NY), 795 (MD)

SectorZ

Quote from: jp the roadgeek on March 07, 2018, 01:55:29 AM
Quote from: Rothman on March 06, 2018, 09:15:15 PM
Meh.  The only exit I can think of that would make sense for the Pike is at US 20 and MA 8, but AADT probably doesn't warrant it and I believe there has been local opposition to it.

Could also put one at MA 19 or MA 67 in Warren.  There's a 15 mile gap between MA 32 in Palmer and I-84 in Sturbridge.  The US 20/MA 8 Exit makes sense for those of us driving up to Albany from areas west of Hartford who would rather use CT/MA 8 and not have to backtrack to I-91 to get to the Pike.

In the "if you build it they will come" mentality, the thought of putting one at or near MA 56 to make a roadway up to Worcester airport has been thrown around for years.

roadman65

I think the Mass Pike where you have the 30 mile stretch of exit less freeway through the Berkshires is a definite feat as for the very populated north-east part of the US that has a good ratio for the region.

In a state like Texas or Utah, it would not be a big deal.

You got to go with what is around the region.

As Jeff says earlier I-295 having 15 exits in only 13 miles is overkill and from living in NJ most of my young life I always thought that was extreme.  However, that was built before the interstate system was created as it was originally to be just an expressway for US 130 to bypass Gibbstown and Paulsboro so it was grandfathered in.  If it were built the same time as the rest of I-295 it would have not had and Exit 14 and 15.  16 would be the one for the area and some others in between Paulsboro and Clarksboro massive interchange and 16 would not be.

I heard on here NJDOT wanted to scale back on them but locals did not want to lose their exits, so at most they upgraded the ramps as many had sharp curves to them originally.  Some even used one ramp for on and off traffic painted with a double line in the middle like Exit 14 had before it got upgraded, or for all I know it still may have but more safer grading.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

jeffandnicole

Exits 15, 16A and 16B are still the same: Double yellow line on the ramp, with a 15 or 20 mph advisory speed (which is posted way too late for unsuspecting drivers).  The others have been upgraded to normal interchanges.

jwolfer

Look at the number of exits in the Orlando area on i4 vs FL Turnpike..   the turnpike was built for thru traffic with a ticket system.. and also when built the turnpike was mostly thru orange groves...

Z981


Super Mateo

Quote from: webny99 on March 06, 2018, 08:28:40 PM
That may be true, and I could have left ratios out of it. While the "unnecessary exits" thread linked above was meant for specific locations, the underlying question here is which freeways would flow better with less exits overall. And of course the reverse - which freeways have the fewest exits relative to crossings, and should more exits be added.

If you want a freeway with way too many exits that would likely flow much better with fewer exits, the entire I-90/94 overlap in Chicago is a perfect example.

roadman65

I think Delaware is doing it good with limited exits on the DE 1 Turnpike.  However, DelDOT did give permission for a partial interchange with DE 8, though still spread out.

Also when the last segment of I-78 in both PA and NJ both states agreed to space out the exits to avoid too much population explosion. Only the part where overlapped with PA 309 is a lot of exits in a short stretch all because PA 309 existed there for decades prior to the interstate.  In Bethlehem they did do it good by not interchanging with PA 378 and only having PA 412 as its sole exit.  In Easton they did well too by leaving only one exit and in NJ by not building any interchanges west of US 22.   

NJDOT could have built two interchanges at Carpenters Road and CR 519, but chose to allow all traffic between Phillipsburg and I-78 to facilitate on US 22 even EB.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

Revive 755

For I-64 in Missouri between I-70 and I-270 - about 26 miles - there appears to be a total of 19 crossings.  Only three of these (Ronald Regan Drive and Old Hwy N near the MO 364 interchange; Woods Mill Road next to MO 141) do not have at least one ramp providing access to/from I-64.

For MO 364:  Appears to be 21 crossings in 20 miles, 8 without any ramps, coming down to 7 when Gutermuth Road gets an interchange in near the future.

Scott5114

In Oklahoma, it's fairly uncommon to have a crossing with no ramps. Often the road simply dead-ends on either side of the Interstate.
uncontrollable freak sardine salad chef

webny99

See, I'd question why a road is even labeled "limited access" if there's access to every cross street.

Obviously the thruway is the extreme in this regard, but as a general rule I think having crossings outweigh exits is a good thing. Among other reasons, it's better for traffic flow, and cuts down on overlapping signage and resulting confusion.

Scott5114

Quote from: webny99 on March 11, 2018, 04:17:44 PM
See, I'd question why a road is even labeled "limited access" if there's access to every cross street.

Because there are no driveways, at-grade crossings, etc.
uncontrollable freak sardine salad chef

jeffandnicole

Quote from: Scott5114 on March 13, 2018, 03:42:21 AM
Quote from: webny99 on March 11, 2018, 04:17:44 PM
See, I'd question why a road is even labeled "limited access" if there's access to every cross street.

Because there are no driveways, at-grade crossings, etc.

Back in the early 90's, well after US 130 was also given the I-295 designation in South Jersey, there was still a section of highway around Exit 21 - 23 where businesses had driveways directly onto I-295.  The state obviously had to close off that access as an interstate highway needs to be limited access.  Of course those businesses weren't too happy about it.  It became one of the few stretches of highway in NJ with some sort of frontage road system.

webny99

Quote from: Scott5114 on March 13, 2018, 03:42:21 AM
Quote from: webny99 on March 11, 2018, 04:17:44 PM
See, I'd question why a road is even labeled "limited access" if there's access to every cross street.

Because there are no driveways, at-grade crossings, etc.

Well, that's a given, but the term infers that there are potential access points but no access. If that's not the case (in other words, if every potential access point has access), I see it as somewhat of an issue.
Dead ends on either side of a freeway seems like the cheap route to me.

ET21

I think maybe every 3-4 miles an exit would be good in urban areas. Shorter than that you start running into the weaving issues that jams traffic (Look at I-90/94 or 290 in Chicago), and longer than 5 miles you run the risk of overloading the exit because everyone needs to get off there (I-294 with 95th Street and Cicero Ave as prime examples).

Outside of cities, up to the density of rural towns in the interstates vicinity, maybe one every 5 or 10 miles
The local weatherman, trust me I can be 99.9% right!
"Show where you're going, without forgetting where you're from"

Clinched:
IL: I-88, I-180, I-190, I-290, I-294, I-355, IL-390
IN: I-80, I-94
SD: I-190
WI: I-90, I-94
MI: I-94, I-196
MN: I-90

Scott5114

Quote from: webny99 on March 13, 2018, 10:29:35 AM
Quote from: Scott5114 on March 13, 2018, 03:42:21 AM
Quote from: webny99 on March 11, 2018, 04:17:44 PM
See, I'd question why a road is even labeled "limited access" if there's access to every cross street.

Because there are no driveways, at-grade crossings, etc.

Well, that's a given, but the term infers that there are potential access points but no access. If that's not the case (in other words, if every potential access point has access), I see it as somewhat of an issue.

It doesn't infer that at all, though. The Lake Pontchartrain Causeway is limited access, despite the fact that there are no potential access points in the middle of a lake.

Quote
Dead ends on either side of a freeway seems like the cheap route to me.

uncontrollable freak sardine salad chef



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