Talking interstate highway history here, obviously. Question: how smart was your state in directing its road-building budget toward the interstate highways in the most intelligent way possible, i.e. in the state's best interest, from the start to, say, 1980?
I'd say Mississippi pretty much sucked, as you can see if you peruse the maps archive at gomdot.com. I think the mismanagement probably owes to our old highway district system, by which each of three districts in the state had almost absolute control on the use of highway funds within those same districts.
The dumbest thing our state did was - in the late 50s and well before anything other than the freeway through north Jackson that appears to have run only from Woodrow Wilson to County Line back in the day - start its first work on I-55 at the state line, just south of Memphis. A long stretch of that interstate was complete before Jackson had a stretch of the road as far as Canton! To give just one, rather small example of why this was so monumentally dumb, consider that for about a decade, Christmas shoppers in North Mississippi, wanting the easiest and quickest route to a city mall to do their shopping, had the option of a modern, divided four-lane highway that mostly bypassed all the towns on the way to Memphis (just outside Mississippi, of course), or an old, mostly shoulderless two-lane route to Jackson, passing directly through the downtowns of each and every single hamlet, village, etc, in between.
So I'd say on a scale of A+ to F, Mississippi comes in at about a midlin' D. It's saved from an F by the fact that other routes were built more wisely, but that one glaring mistake makes us look remarkably dumb!
Okay, I realize it's been more than half a century, but that kinda dumbness is monumental and needs to be remembered!
I'm thinking maybe some other folks have gripes like this about other states.
The laying out of Pennsylvania's modern Interstates was excellent, although the Department of Highways just took the Turnpike Commission's plans and built the roads.
The financing of said Interstates was where they dropped the ball, and why PennDOT became notorious for poor roadways. Bonds were sold to finance construction of the system, but when they matured, paying their interest alone would have equaled somewhere around 150% of PennDOT's budget. It wasn't until the 1980s when the Legislature stepped in to right their budgetary ship that maintenance of existing and construction of new roadways (I-78 in the Lehigh Valley, I-279 in Pittsburgh, I-476/I-676 in Philadelphia) began to move forward.
Knowing this history, it made me cringe a few years back when PennDOT was selling bonds to finance bridge replacement projects.
California did pretty good, mostly keeping interstates in the populated areas.
Of course, there is I-238.
Florida had the Turnpike before the interstate system - at least the Miami to Fort Pierce stretch. Given the nature of our state, there were really only so many places they could put the interstates. I'm happy with the way things worked out.
Quote from: Quillz on September 01, 2011, 04:00:01 PM
California did pretty good, mostly keeping interstates in the populated areas.
Of course, there is I-238.
there's also I-710.
Illinois statred the Expressways and Tollways before the Interstates and then pushed and pushed for more milage and later came out with a post interstate plan(which has been discussed a lot under Midwest). The only interstate not completed was the Crosstown Expressway and it was not on the original plan.
There was a 78,000 mile Interstate plan and Illinois built all of those. It is still buildling a lot of the others supplementals as 4 lane divideds or Tollways. Lets say they have lost their old ambition
Here in North Texas, there are a couple of instances of "goof-ups".
One is Loop 217 in SW Ft Worth. Part of it was taken over by (LOOP) I-820, but part of it was not. A portion of the part that was not taken over was divided, while some was controlled access. The controlled access is now not nessessary due to being bypassed by I-820. It was also remunbered as part of SH 183, which doesn't make good sense and is very confusing signage-wise.
http://maps.google.com/maps?hl=en&ll=32.694649,-97.428217&spn=0.052585,0.10952&z=14&vpsrc=6 (http://maps.google.com/maps?hl=en&ll=32.694649,-97.428217&spn=0.052585,0.10952&z=14&vpsrc=6)
The other big one is the US 75/ I-45 situation in south Dallas. US 75 was upgraded to some divived, some controlled access, but I-45 bypassed this section, leaving over-built conditions on US 75. Also, US 175 does not connect to I-45 like it needs to. It will, however be connected in the future, and the redundant freeway will be downgraded to a BLVD. Note: The former US 75 is now SH 310 south of US 175. US 175 took over part of the former US 75 up to Downtown.
http://maps.google.com/maps?hl=en&ll=32.678396,-96.679687&spn=0.210377,0.43808&z=12&vpsrc=6 (http://maps.google.com/maps?hl=en&ll=32.678396,-96.679687&spn=0.210377,0.43808&z=12&vpsrc=6)
Quote from: realjd on September 01, 2011, 05:10:25 PM
Florida had the Turnpike before the interstate system - at least the Miami to Fort Pierce stretch. Given the nature of our state, there were really only so many places they could put the interstates. I'm happy with the way things worked out.
Florida did pretty well. Especially getting I-75 all the way down the West coast instead of stopping at St Pete like it did for so long. At the planning stages Orlando wasnt that big, but I would like to see the OOCEA roads be I-x04. ( 417=204, 408=104 and 528=404).
What is amazing to me is Florida making the US highways plow right through town instead of building bypasses like GA... like 301 thru Starke... it has been problems for years
New Jersey had some good plans but the whole Somerset Freeway cancellation is a Biiiiiiig F-up. I-95 through Mercer and Somerset Counties would have prevented lots of US 1, US 206 and NJ 31 congestion. The NJTP would be there for thru traffic and I-95 would be there for local commuter traffic. The sprawl that the NIMBYs wanted to prevent by fighting the freeway happened anyway with a network of 2 lane country roads
Quote from: agentsteel53 on September 01, 2011, 05:18:45 PM
Quote from: Quillz on September 01, 2011, 04:00:01 PM
California did pretty good, mostly keeping interstates in the populated areas.
Of course, there is I-238.
there's also I-710.
Can't really blame Caltrans for that, though, it's the Pasadena NIMBYs that blocked it.
Quote from: Quillz on September 01, 2011, 06:31:52 PM
Can't really blame Caltrans for that, though, it's the Pasadena NIMBYs that blocked it.
well, it certainly results in unintelligent evolution of the interstate system!
Quote from: agentsteel53 on September 01, 2011, 06:42:56 PM
Quote from: Quillz on September 01, 2011, 06:31:52 PM
Can't really blame Caltrans for that, though, it's the Pasadena NIMBYs that blocked it.
well, it certainly results in unintelligent evolution of the interstate system!
True.
The original Bay Area propositions made a lot of sense, too, creating a complete freeway solution around San Francisco. But it was another idea killed by NIIMBYs, although one I do agree with.
It's not just interstates, though. NIMBYs also blocked completion of CA-52, 56, 67, 125, etc. And then you have highways like CA-39 and 144 with portions that have been closed forever. All of that certainly leads to unintelligent highway expansion, but a lot of it is seemingly unavoidable.
Oregon did very well with I-5 early on, having it done by 1965. There are not enough lanes on it today. I-84 took longer to finish but it took care of the E-W route leading out from our one major metro area, with the section from PDX to The Dalles being done in relatively short order back in the Sixties. I-84 improvements in PDX/Multnomah County have made the metro part of the freeway decent for the traffic load it bears. I-82 took forever to get built and very few folks would use the first stretch who were coming into the area around Hermiston since there are shorter routes to get to I-82 from I-84 without the need to go to the "in-the-middle" freeway-to-freeway interchange.
The layout of the routes was mostly good although one running from Eugene to Ontario would have been nice for geographic reasons as it would have bisected the state while I-84 skirted the northern edge until it headed SE after getting past Pendleton.
For 3DI routes, I-105, I-205 and I-405 were properly routed but they were not built with enough lanes. The cancellation of I-305 did not hurt Salem too bad since the Salem Parkway essentially fulfilled the same function along the same routing. Missing I-505 on the map did not hurt either since there is still a stub freeway, which is all I-505 would have been, coming off of I-405 and it turns into a decent expressway through an industrial sector. The real loss was not having the Mt. Hood Freeway in SE PDX being built.
From git 'er done to today's bandaid solutions shows how far ODOT has fallen down on the job. They would have been given a grade of A- for what they did in the Sixties, when so much obsolete road needed to be dealt with. Every decade since then has seen regression and the slide downwards keeps gathering momentum.
Rick
Quote from: Quillz on September 01, 2011, 06:51:44 PM
The original Bay Area propositions made a lot of sense, too, creating a complete freeway solution around San Francisco. But it was another idea killed by NIIMBYs, although one I do agree with.
480 around the Embarcadero and 80 through the Panhandle were pretty superfluous, but the original 280 proposal probably still would be useful had it been constructed.
Of the original Bay Area routes proposed...
5W - exists today as 580, the MacArthur segment existed as US 50 before the Interstates though
80 - exists east of US 101, though the segment from 101 to around Route 123 predates the Interstate system as US 40
280 - built between Route 17 in San Jose and Route 1 in San Francisco, segment from Route 1 split to US 101 canceled in 1968 in favor of Southern Freeway routing (which was mostly built except for the portion to I-80). In San Jose, eventually extended east to 101 at Story Road (and the post-1965 680 alignment)
480 - built to Broadway, demolished 1991 after the 1989 earthquake
680 - built between 80 in Vallejo and Route 262 in Fremont; segment from Benicia to Vallejo became 780 in 1976 as 680 took over the last portion of Route 21 north of Benicia. Segment from Fremont to San Jose originally would've been via today's 262/880, but was rerouted onto new-terrain alignment to Story Road from 1965 on. (262 has never been fully converted to freeway)
380, 880, and 980 are all later additions to the system.
Quote from: TheStranger on September 01, 2011, 07:24:25 PM
480 around the Embarcadero and 80 through the Panhandle were pretty superfluous, but the original 280 proposal probably still would be useful had it been constructed.
where is the panhandle?
also, didn't the Embarcadero present a full-freeway option to traverse the city from the south to the Golden Gate Bridge? 101 to 80 to 480 back to 101? or was it never fully completed to the Golden Gate?
to me, the major lack of freeways in the Bay Area are:
37 corridor
101 to the Golden Gate Bridge
80-580 direct connection to San Rafael through Richmond
and then a lot of auxiliary freeways to shore up the fact that even the freeways which do exist are quite badly clogged. I don't know really where I'd put them, but they seem to be quite necessary. getting into the city from the north or the west is next to impossible. maybe another bay bridge from Point Richmond to Angel Island? also, freeways along the 1, 101, and 480 corridors could hopefully diminish the traffic load on a lot of surface streets.
Quote from: agentsteel53 on September 01, 2011, 07:36:26 PMalso, didn't the Embarcadero present a full-freeway option to traverse the city from the south to the Golden Gate Bridge? 101 to 80 to 480 back to 101? or was it never fully completed to the Golden Gate?
Nope--city street running was still necessary to get to the Golden Gate Bridge. (I remember the Embarcadero since my first visit to SF was in 1988, before Loma Prieta and all that.) In fact, San Francisco never had a connection between the south end of the Golden Gate Bridge and the east end of the Bay Bridge that was developed entirely to full freeway standard and within the city itself.
Quote80-580 direct connection to San Rafael through Richmond
I'm assuming you are talking about the lack of a direct connection between I-80 westbound and I-580 westbound. It strikes me that this lack inconveniences mainly people who live in the East Bay, who at least have the option of deadheading around the south end of the I-80/I-580 concurrency if they absolutely
must get to Marin County and points north by full freeway. For long-distance traffic a SR 37 corridor developed up to full freeway standard would be nice, but Google Maps shows SR 37 with canals on either side for considerable distances (which tends to curtail ribbon development), only three or four intersections which seem important enough to rate traffic signals, and some grade separations.
No evolution here. It was designed from start to end.
Quote from: Quillz on September 01, 2011, 04:00:01 PM
California did pretty good, mostly keeping interstates in the populated areas.
I wonder about the re-routing of I-5 off the US-99 corridor in the San Joaquin Valley. I suppose they did that to create a faster route between Los Angeles and San Francisco/Sacramento (SF especially, since the US-101 corridor wasn't added to the Interstate system), but leaving Fresno, Bakersfield, Modesto, Visalia off the Interstate system entirely seems odd. Even in 1950, Fresno had nearly 100,000 people - not huge, but certainly a reasonably-sized city for the time, and I'm sure was a major packing and shipping center for the region.
Quote from: agentsteel53 on September 01, 2011, 07:36:26 PM
Quote from: TheStranger on September 01, 2011, 07:24:25 PM
480 around the Embarcadero and 80 through the Panhandle were pretty superfluous, but the original 280 proposal probably still would be useful had it been constructed.
where is the panhandle?
Fell and Oak Streets east of Golden Gate Park, grassy area that would have been obliterated by the 80 extension. I think most people today would be surprised that it wasn't the Embarcadero that was the most controversial proposal, but the Western Freeway.
I've mentioned before that this would have been way more useful had the 49ers stayed at Kezar Stadium (not too far from the Panhandle, in the southeast edge of Golden Gate Park) than moving to Candlestick about 2-3 years after the proposal was canceled.
Quote from: agentsteel53 on September 01, 2011, 07:36:26 PM
also, didn't the Embarcadero present a full-freeway option to traverse the city from the south to the Golden Gate Bridge? 101 to 80 to 480 back to 101? or was it never fully completed to the Golden Gate?
The gap that was never completed is basically from the western terminus of Marina Boulevard east to where 480 ended at Broadway. (The existing segment of the 101 freeway - soon to be upgraded as Presidio Parkway - along Doyle Drive from 1 to Marina Boulevard would have been part of this full 480 routing). For this reason, prior to 1991, Lombard Street and Richardson Avenue were actually legislatively Route 480 despite always having been signed as US 101!
Quote from: agentsteel53 on September 01, 2011, 07:36:26 PM
to me, the major lack of freeways in the Bay Area are:
37 corridor
101 to the Golden Gate Bridge
80-580 direct connection to San Rafael through Richmond
and then a lot of auxiliary freeways to shore up the fact that even the freeways which do exist are quite badly clogged. I don't know really where I'd put them, but they seem to be quite necessary. getting into the city from the north or the west is next to impossible. maybe another bay bridge from Point Richmond to Angel Island? also, freeways along the 1, 101, and 480 corridors could hopefully diminish the traffic load on a lot of surface streets.
About 10 years ago, there was a Chronicle article mentioning some local folks had suggested tunnels for the 1 and 101 corridors - and even one through the Panhandle. Obviously that didn't go much of anywhere, but that it was even suggested at all was a welcome surprise. 1 probably is the more important gateway to the GGB but I could see that changing if the shorter 101 ends up being the only viable option for a tunnel if that idea ever comes back around. (It was also proposed as a tunnel in the early 1960s as well, covering a gap from Richardson Avenue to the Central Freeway's old terminus at Franklin and Turk.)
37's issue isn't so much that it isn't a freeway in its middle segment, but that it is a two lane road with no passing areas (after originally being a very dangerous 3 lane road). It was submitted in the late 1940s/early 1950s as a proposed Interstate but rejected, when it was still Route 48. Adding passing lanes probably would be enough to fix the bottleneck there but environmentalists have been firmly against any widening in the area.
80 to 580...I know the Richmond Parkway (locally built along the unsigned Route 93 corridor) tends to cover those movements but most direct would be some ramp along Cutting Boulevard where the two freeways first parallel for a mile or two.
Quote from: DTComposerI wonder about the re-routing of I-5 off the US-99 corridor in the San Joaquin Valley. I suppose they did that to create a faster route between Los Angeles and San Francisco/Sacramento (SF especially, since the US-101 corridor wasn't added to the Interstate system), but leaving Fresno, Bakersfield, Modesto, Visalia off the Interstate system entirely seems odd. Even in 1950, Fresno had nearly 100,000 people - not huge, but certainly a reasonably-sized city for the time, and I'm sure was a major packing and shipping center for the region.
IIRC, the West Side corridor got Interstate funding specifically so that there would be two, instead of one, major divided highway pathways through the San Joaquin Valley. As a result of that alignment switch however, I'm not sure that SF-Fresno could be taken at all using only freeways for many years, the 120 bypass of Manteca being a much more recent construction.
Quote from: TheStranger on September 02, 2011, 01:27:04 AM
I'm not sure that SF-Fresno could be taken at all using only freeways for many years
It still can't be.
I would say California has done pretty well. However, we have a TON of state route freeways that could easily be Interstates, not to mention save Caltrans some money on Maintenance. I would say it's continuing to evolve pretty well, with CA 210 built to create a continuous I-210, and the upgrading of CA 99 to I-7 or I-9 which would provide a major interstate connection and a worthy addition to Interstate miles.
Quote from: NE2 on September 02, 2011, 01:37:16 AM
It still can't be.
I'm willing to forgive that one brief gap in 99 around Atwater, just because upgrading it to full freeway might result in the death of one of the last US-99 signs in the state.
Post Merge: September 02, 2011, 02:11:02 AM
Quote from: TheStranger on September 02, 2011, 01:27:04 AM
Fell and Oak Streets east of Golden Gate Park, grassy area that would have been obliterated by the 80 extension.
Fell/Oak is one of the faster arterials in San Francisco. The city isn't just missing fully-limited-access freeways, it is also significantly missing arterial routes. A lot of the time I find myself on little two-lane or four-lane roads that are supposed to be major but certainly are not designed that way. See Divisadero, and even 19th. Though 19th's problems are mainly that there are traffic lights on
every block with no real synchronization scheme. I'm not sure structurally what is different between 19th and, say, Western Ave or Vermont Ave in Los Angeles, but one moves and the other does not.
Quote37's issue isn't so much that it isn't a freeway in its middle segment, but that it is a two lane road with no passing areas (after originally being a very dangerous 3 lane road).
I'd be fine with it being a four-lane expressway, with maybe even a traffic light or two where they currently are, but the middle segment is one of those roads (152 is another) where I always count down the tenths of a mile until it is
finally over.
the last several weeks I've tried two approaches to the southern end of San Francisco (almost Daly City) from Sacramento: 80 to 37 to 101, and 80 to Richmond Parkway to 580 to 101. I'm now thinking that the most sensible approach may be 680 to 580 to 238 to 880 to 92!!
QuoteIt was submitted in the late 1940s/early 1950s as a proposed Interstate but rejected, when it was still Route 48.
so there was a Bear 48? For some reason I had thought the route was devised around 1959. At one point I owned a white 48 shield from 1960.
Quote80 to 580...I know the Richmond Parkway (locally built along the unsigned Route 93 corridor) tends to cover those movements but most direct would be some ramp along Cutting Boulevard where the two freeways first parallel for a mile or two.
Richmond Parkway is actually quite fast-moving. My major concern is the long connector from 580 WB to 101 SB. Francis Drake Blvd or whatever it is called. That definitely needs to be improved. There also needs to be a sign on 580 WB that says "Francis Drake Blvd is not just suggested. It is also not just highly recommended. It is the
only to get to 101 without making a U-turn!!!" (this as opposed to those trailblazers on CA-33 and other roads in the central valley which say "I-5 north 16 miles" along one northbound road, and "I-5 south 18 miles" along one eastbound road; but you can certainly get to I-5 north and south from either.
Quote from: 3467 on September 01, 2011, 05:27:52 PM
Illinois statred the Expressways and Tollways before the Interstates and then pushed and pushed for more milage and later came out with a post interstate plan(which has been discussed a lot under Midwest). The only interstate not completed was the Crosstown Expressway and it was not on the original plan.
There was a 78,000 mile Interstate plan and Illinois built all of those. It is still buildling a lot of the others supplementals as 4 lane divideds or Tollways. Lets say they have lost their old ambition
Actually,
The Lake Shore Drive Alignment of I-494 was on the original plan and it was traded for the Crosstown Route in 1963.
The Original Route Description
The original I-494 started at the Ohio/Ontario feeder ramps at I-90/94, then it proceed Eastward with a tunnel to Lake Shore Drive, then if proceeded South along LSD to Stony Island Avenue to I-90 (Chicago Skyway).
Quote from: agentsteel53 on September 02, 2011, 01:50:39 AM
Quote from: NE2 on September 02, 2011, 01:37:16 AM
It still can't be.
I'm willing to forgive that one brief gap in 99 around Atwater, just because upgrading it to full freeway might result in the death of one of the last US-99 signs in the state.
Wow, there's one!? Tell me more (private message/email is fine)!
Quote from: agentsteel53
Post Merge: December 31, 1969, 09:59:59 PM
Quote from: TheStranger on September 02, 2011, 01:27:04 AM
Fell and Oak Streets east of Golden Gate Park, grassy area that would have been obliterated by the 80 extension.
Fell/Oak is one of the faster arterials in San Francisco. The city isn't just missing fully-limited-access freeways, it is also significantly missing arterial routes. A lot of the time I find myself on little two-lane or four-lane roads that are supposed to be major but certainly are not designed that way. See Divisadero, and even 19th. Though 19th's problems are mainly that there are traffic lights on every block with no real synchronization scheme. I'm not sure structurally what is different between 19th and, say, Western Ave or Vermont Ave in Los Angeles, but one moves and the other does not.
19th's lack of synchronization probably relates to the city's desire to keep speeds low there. For comparison, Great Highway on the oceanfront just a mile or two away has a perfect synchronization scheme to go 37 MPH without stopping!
Quote from: agentsteel53
the last several weeks I've tried two approaches to the southern end of San Francisco (almost Daly City) from Sacramento: 80 to 37 to 101, and 80 to Richmond Parkway to 580 to 101. I'm now thinking that the most sensible approach may be 680 to 580 to 238 to 880 to 92!!
680-24-580-80-5th Street/6th Street-280 is one way to do it that avoids the 101/80 mess, but not the Bay Bridge mess at all.
Quote from: agentsteel53
QuoteIt was submitted in the late 1940s/early 1950s as a proposed Interstate but rejected, when it was still Route 48.
so there was a Bear 48? For some reason I had thought the route was devised around 1959. At one point I owned a white 48 shield from 1960.
Correct, bear 48, I don't know if it was original to the 1934 numbering, but it DID represent today's Route 37 from Route 121 to I-80. (Route 121 north of there was pre-1964 Route 37, while Route 37 between 101 and 121 has been part of the route from the very beginning.)
Quote from: agentsteel53
Quote80 to 580...I know the Richmond Parkway (locally built along the unsigned Route 93 corridor) tends to cover those movements but most direct would be some ramp along Cutting Boulevard where the two freeways first parallel for a mile or two.
Richmond Parkway is actually quite fast-moving. My major concern is the long connector from 580 WB to 101 SB. Francis Drake Blvd or whatever it is called. That definitely needs to be improved. There also needs to be a sign on 580 WB that says "Francis Drake Blvd is not just suggested. It is also not just highly recommended. It is the only to get to 101 without making a U-turn!!!" (this as opposed to those trailblazers on CA-33 and other roads in the central valley which say "I-5 north 16 miles" along one northbound road, and "I-5 south 18 miles" along one eastbound road; but you can certainly get to I-5 north and south from either.
Yeah, if Sir Francis Drake between 101 and 580 was at least upgraded to an expressway, it'd be a much more useful connector (the odd half-limited access, half-grade level interchange that was built when this was the first part of an unfinished Route 251 has serious issues with backups).
Quote from: TheStranger on September 03, 2011, 01:21:40 AM
I'm willing to forgive that one brief gap in 99 around Atwater, just because upgrading it to full freeway might result in the death of one of the last US-99 signs in the state.
it's well-known. the shields are covered up ... poorly.
(//www.aaroads.com/shields/img/CA/CA19640991i1.jpg)
as far as I know, there are no unmodified references to US-99 left in California. There is one sign in Seattle (also very well known) and a 99W in Oregon that is less well-known but does indeed date to the 60s.
I think it's now a full freeway past Atwater; just recently some at-grades between Livingston and Atwater disappeared. I'm talking about the at-grades between Merced and Chowchilla.
Quote from: agentsteel53 on September 03, 2011, 01:28:03 AM
as far as I know, there are no unmodified references to US-99 left in California. There is one sign in Seattle (also very well known) and a 99W in Oregon that is less well-known but does indeed date to the 60s.
There's also that sign goof near Fresno's airport with the US 99 shield...
And we had the one from 2008-2009 on the WX (Capital City) Freeway that I was able to get a pic of before it was corrected.
I like Hawaii's idea of numbering their interstates in the order they were built, not their direction.
Quote from: 3467 on September 01, 2011, 05:27:52 PM
Illinois statred the Expressways and Tollways before the Interstates and then pushed and pushed for more milage and later came out with a post interstate plan(which has been discussed a lot under Midwest). The only interstate not completed was the Crosstown Expressway and it was not on the original plan.
There was a 78,000 mile Interstate plan and Illinois built all of those. It is still buildling a lot of the others supplementals as 4 lane divideds or Tollways. Lets say they have lost their old ambition
LOTS of help from Cook County and the IL State Toll Highway Authority to build the radial I-routes into and around Chicago in the early days. The definitive web site for their history is www.cookexpressways.com.
Downstate, the interstates were completed in fairly logical order, with I-55 being the last "legacy" interstate, replacing a serviceable 4-lane expressway in US 66. With the Supplemental Freeway routes, I-39 and I-72 came out OK. US 51 south of Bloomington has turned into an endless mess of stoplights and reduced speed zones; some old timers at IDOT District 5 regretted what they allowed to happen around Clinton and in Forsyth.
Quote from: Quillz on September 03, 2011, 06:20:25 PM
I like Hawaii's idea of numbering their interstates in the order they were built, not their direction.
Coincidence. The numbering was set long before anybody realized that H-3 would be much more controversial, and take much longer to build, than H-2. Also, while part of H-1 was open (as a non-Interstate freeway) even before Hawaii became a state, the rest of it wasn't completed until after H-2 was completed.
I-H201 ruins the whole thing too; if it was build order, one of them would need to be renumbered I-H4!.
Quote from: TheStranger on September 03, 2011, 01:21:40 AM
19th's lack of synchronization probably relates to the city's desire to keep speeds low there. For comparison, Great Highway on the oceanfront just a mile or two away has a perfect synchronization scheme to go 37 MPH without stopping!
Yep, I'm pretty sure they de-synchronized the lights along 19th about 10 years ago. I know they did so along Oak/Fell, where they used be perfectly synchronized for 43MPH (!) all the way from GG Park to the freeway ramps. (Now they are a more appropriate ~25MPH with several mandatory reds.)
Quote from: flowmotion on September 04, 2011, 01:30:02 PM
Yep, I'm pretty sure they de-synchronized the lights along 19th about 10 years ago. I know they did so along Oak/Fell, where they used be perfectly synchronized for 43MPH (!) all the way from GG Park to the freeway ramps. (Now they are a more appropriate ~25MPH with several mandatory reds.)
I can understand 43mph being a bit on the fast side, but why bring it all the way down to 25 and put in mandatory reds? How does that help traffic flow at all??
Quote from: deanej on September 04, 2011, 12:17:34 PM
I-H201 ruins the whole thing too; if it was build order, one of them would need to be renumbered I-H4!.
Although if you read the zero as though it were the letter "O," the name sounds very appropriate for a highway located on an island in the middle of the ocean (think back to high school science classes).
Quote from: deanej on September 04, 2011, 12:17:34 PM
I-H201 ruins the whole thing too; if it was build order, one of them would need to be renumbered I-H4!.
H-201 should've been numbered H-4 in the first place, but that would've thrown off the completion order either way, since it was completed seven years before H-3.
"Build order" is kind of ambiguous, anyway -- do you count when it started, or when it finished? And when is "started"? Especially for H-201, which alone among Hawaii's Interstates is basically an upgrade of a road that existed before the automotive era.
Connecticut never planned interstates. They planned freeways and some of them ended up with interstate designations.
As for intelligent evolution, well... the planning was sound, but local opposition has interfered with plans actually coming to fruition. We have a lot of unbuilt or unfinished freeways.
Quote from: agentsteel53 on September 04, 2011, 02:56:37 PM
I can understand 43mph being a bit on the fast side, but why bring it all the way down to 25 and put in mandatory reds? How does that help traffic flow at all??
I think the lights are synced for 25 MPH not for traffic flow but for pedestrian safety. Over the past couple of years, there's been an alarming increase in pedestrian fatalities on 19th Ave.
Quote from: myosh_tino on September 05, 2011, 12:21:14 AM
I think the lights are synced for 25 MPH not for traffic flow but for pedestrian safety. Over the past couple of years, there's been an alarming increase in pedestrian fatalities on 19th Ave.
sure, but what's the advantage of the mandatory reds?
Quote from: agentsteel53 on September 05, 2011, 02:49:24 AM
...what's the advantage of the mandatory reds?
That's a damn good question, but it might take an engineer or a physicist to explain it. I've heard it discussed by people who know a lot more about this sort of thing than I do, and although I certainly can't answer your question, I can tell you that it has something to do with fluid dynamics.
The rules of fluid dynamics apply to traffic flow in ways that totally surprised me. For another example I can't make sense of unless I'm actively listening to a dumbed-down explanation: when mntc projects require a freeway to temporarily reduce the number of forward lanes - let's say from two to one - there's always that idiot approaching it during heavy traffic in the lane that's about to end, who at the very last moment manages to shove his or her way into the remaining thru lane, while everyone else patiently waits their turn. Well, somehow you can use fluid dynamics to explain how that idiot is doing everybody a favor by making traffic flow more smoothly. Really.
that, despite not being intuitive, makes sense because I had studied that kind of thing before :sombrero:
basically, I think the red lights will break up standing waves where traffic slows down pathologically at a given point - better to slow everyone down from 25 to 0 for one minute at various spots, than from 25 to 5 for three minutes at the same spot.
but that only works if timed correctly. somehow, I cannot imagine 19th street is timed correctly. or, maybe everyone in San Francisco is "that idiot" driver* and this really is the best we can do.
*practical experience suggests this to, indeed, be the case
Quote from: berberry on September 05, 2011, 12:21:46 PM
The rules of fluid dynamics apply to traffic flow in ways that totally surprised me. For another example I can't make sense of unless I'm actively listening to a dumbed-down explanation: when mntc projects require a freeway to temporarily reduce the number of forward lanes - let's say from two to one - there's always that idiot approaching it during heavy traffic in the lane that's about to end, who at the very last moment manages to shove his or her way into the remaining thru lane, while everyone else patiently waits their turn. Well, somehow you can use fluid dynamics to explain how that idiot is doing everybody a favor by making traffic flow more smoothly. Really.
Based on experience, that's true. At various times I've reverse commuted over the Golden Gate Bridge and through the Caldecott Tunnel (CA24), both roads narrowing from 4 lanes to 2 through the bottleneck. The 'correct way' was to stay left as long as possible and then take turns merging where the lane disappeared. People who merged over early would cause the lane behind them to hit their brakes and stop the flow.
However, I'm guessing the 19th Ave logic is that they don't want people accelerating over several blocks, only to slam on their brakes or attempt to run the reds. So they stop people every few blocks to keep speeds down.
Quote from: flowmotion on September 05, 2011, 05:04:18 PM
However, I'm guessing the 19th Ave logic is that they don't want people accelerating over several blocks, only to slam on their brakes or attempt to run the reds. So they stop people every few blocks to keep speeds down.
I recall that the state of California actually had a big debate with SF over this (as SF clearly wanted to lower the limit on 19th, while Caltrans did not). What doesn't help is that beyond Sloat Boulevard, alternates to 19th are hard to come by:
- Great Highway only really works if you're coming in from the coastal cities of San Mateo County (i.e. Pacific, western Daly City and San Bruno) as coming in from 280 requires cutting over on surface streets with plenty of lights (John Daly Boulevard, Lake Merced Boulevard, Brotherhood Way)
- Sunset Boulevard, while less busy than the 19th, stops at Lincoln Way at the south edge of Golden Gate Park. I recently used it to avoid 19th after heading southbound on the short Park Presidio Boulevard segment of Route 1.
- Junipero Serra Boulevard ends at Sloat Boulevard, so north of there requires the narrower 7th Avenue to get past Golden Gate Park, not particularly designed for through traffic at all. (IIRC, Serra and 7th was the planned corridor for the pre-1968 I-280/Junipero Serra Freeway extension north of its final terminus at Brotherhood Way)
- If one wanted to try skipping the Sunset altogether, they could use 280 north to San Jose Avenue (the corridor for the unbuilt Mission Freeway, which is expressway standard to 30th Street) to Dolores Street to Market to Franklin up to Lombard/101, but plenty of lights on Lombard, and stop signs on Dolores stymie flow.
Being new to Indiana. I have wondered why I-64 went further south instead of following US-150 most of the way. Ok Evansville might have had a bit of pull.
Shawn P - There are other postings on this site that go into detail on the location of I-64. Being from Evansville, I have always had an interest in that subject. There is a written history on the Interstate System in Indiana that provides a definitive history on the location of I-64. I don't remember what topic it is located in, but you will find it in the forum in one of the regional pages (Ohio Valley, I think). It will answer all of your questions and more.
Here's one of the links below.
http://docs.lib.purdue.edu/jtrp/1415/
Quote from: Rick Powell on September 04, 2011, 01:51:11 AM
Quote from: 3467 on September 01, 2011, 05:27:52 PM
Illinois statred the Expressways and Tollways before the Interstates and then pushed and pushed for more milage and later came out with a post interstate plan(which has been discussed a lot under Midwest). The only interstate not completed was the Crosstown Expressway and it was not on the original plan.
There was a 78,000 mile Interstate plan and Illinois built all of those. It is still buildling a lot of the others supplementals as 4 lane divideds or Tollways. Lets say they have lost their old ambition
LOTS of help from Cook County and the IL State Toll Highway Authority to build the radial I-routes into and around Chicago in the early days. The definitive web site for their history is www.cookexpressways.com.
Downstate, the interstates were completed in fairly logical order, with I-55 being the last "legacy" interstate, replacing a serviceable 4-lane expressway in US 66. With the Supplemental Freeway routes, I-39 and I-72 came out OK. US 51 south of Bloomington has turned into an endless mess of stoplights and reduced speed zones; some old timers at IDOT District 5 regretted what they allowed to happen around Clinton and in Forsyth.
Cook County effectively built the expressway system, but IDOT's predecessor did do a bit here as well. I-55 from Gardner to Indian Head Park (Exit 227 to Exit 276C) was built by the state as a replacement for US-66 and US-66A in the area by 1956.
Quote from: TheStranger on September 05, 2011, 05:37:11 PM
- If one wanted to try skipping the Sunset altogether, they could use 280 north to San Jose Avenue (the corridor for the unbuilt Mission Freeway, which is expressway standard to 30th Street) to Dolores Street to Market to Franklin up to Lombard/101, but plenty of lights on Lombard, and stop signs on Dolores stymie flow.
Actually the through street is Guerrero, one block over from Dolores Pkwy. (Only reason I menton is because Guerrero is yet another street which used have lights timed for traffic and now likes to stop you every few blocks.)
There are various other ways of getting to the S/W portions of the city. But in the end, if your destination is the GG Bridge, you don't have much choice other than 19th Ave.
Quote from: berberry on September 05, 2011, 12:21:46 PM
Quote from: agentsteel53 on September 05, 2011, 02:49:24 AM
...what's the advantage of the mandatory reds?
That's a damn good question, but it might take an engineer or a physicist to explain it. I've heard it discussed by people who know a lot more about this sort of thing than I do, and although I certainly can't answer your question, I can tell you that it has something to do with fluid dynamics.
Quote from: agentsteel53 on September 05, 2011, 12:33:55 PM
basically, I think the red lights will break up standing waves where traffic slows down pathologically at a given point - better to slow everyone down from 25 to 0 for one minute at various spots, than from 25 to 5 for three minutes at the same spot.
I've taken courses in traffic engineering that have dealt with signal timing and progression. The concept of "mandatory red" was never discussed. The whole objective of signal coordination is to keep traffic moving, so purposefully stopping platoons of traffic multiple times doesn't really make sense with that goal.
I recall a conversation with a signal engineer a few years ago who was talking about some coordinated signal timing of an arterial in the Las Vegas area. He described a point along the coordinated arterial as a "bump", which basically menat that the traffic was likely to get a red at that point. From what he was saying though, it sounded more like the crossing arterial was a higher priority in coordination as opposed to a conscious decision to halt the traffic flow.
One thing that does make some sense though is to use the 'mandatory red' concept in order to 'regroup' the platoon. On a higher-speed arterial, the variations in speeds will eventually lead to the platoon getting more and more spread out. Inserting a red would get the spread out vehicles more closely together. Perhaps the practical application of this is in coordinating cross streets, where you might need platoons to keep grouped in order to move traffic on side streets.
Quote from: berberry on September 05, 2011, 12:21:46 PM
The rules of fluid dynamics apply to traffic flow in ways that totally surprised me. For another example I can't make sense of unless I'm actively listening to a dumbed-down explanation: when mntc projects require a freeway to temporarily reduce the number of forward lanes - let's say from two to one - there's always that idiot approaching it during heavy traffic in the lane that's about to end, who at the very last moment manages to shove his or her way into the remaining thru lane, while everyone else patiently waits their turn. Well, somehow you can use fluid dynamics to explain how that idiot is doing everybody a favor by making traffic flow more smoothly. Really.
The application of fluid dynamics to traffic crosses over a lot more than most people realize.
Flow is primarily a fluid dynamic concept, so analysing "traffic flow" is an obvious connection--in the traffic engineering textbook I've used in grad school, many of the variables used to describe flow, capacity, etc. were the same as those used in my undergrad fluid dynamics class. I wish I had made the connection between the two topics much earlier...I probably would've done better in fluids class.
The merging example is another correct application of fluid dynamics and flow rate, except you need a lot more idiots. I believe it has to do with turbulence in the flow. If you have people merging over at random locations, it interrupts the steady flow at multiple points, causing the slowdown to propigate back upstream. However, if both lanes wait to merge at a single point (i.e. "zipper" merging), the upstream vehicles remain at constant speed and everything flows more smoothly. I believe this was actually studied a few years ago by a state DOT somewhere back east, that found when instructing drivers to merge at a specific point the delay was reduced by a significant amount.
Quote from: roadfro on September 06, 2011, 05:41:57 AM
The merging example is another correct application of fluid dynamics and flow rate, except you need a lot more idiots. I believe it has to do with turbulence in the flow. If you have people merging over at random locations, it interrupts the steady flow at multiple points, causing the slowdown to propigate back upstream. However, if both lanes wait to merge at a single point (i.e. "zipper" merging), the upstream vehicles remain at constant speed and everything flows more smoothly. I believe this was actually studied a few years ago by a state DOT somewhere back east, that found when instructing drivers to merge at a specific point the delay was reduced by a significant amount.
Unfortunately, the people still slow down as they hit the construction and merging 2 lanes to 1 takes time. Throw in a few idiot drivers who don't know what they're doing and you get very long backups.
I read an article about "zipper" merging in the Quad City Times, and I wish I could find it online. Basically, it was a letter to the editor or something asking what the benefits of using the "zipper" at I-74 going into Iowa were. The author of the article said that it wasn't to save time, because it obviously hadn't, but to save distance by theoretically making the backup half as long, preventing backups in other ramps.
Quote from: roadfro on September 06, 2011, 05:41:57 AM
Quote from: berberry on September 05, 2011, 12:21:46 PM
The rules of fluid dynamics apply to traffic flow in ways that totally surprised me. For another example I can't make sense of unless I'm actively listening to a dumbed-down explanation: when mntc projects require a freeway to temporarily reduce the number of forward lanes - let's say from two to one - there's always that idiot approaching it during heavy traffic in the lane that's about to end, who at the very last moment manages to shove his or her way into the remaining thru lane, while everyone else patiently waits their turn. Well, somehow you can use fluid dynamics to explain how that idiot is doing everybody a favor by making traffic flow more smoothly. Really.
The application of fluid dynamics to traffic crosses over a lot more than most people realize. Flow is primarily a fluid dynamic concept, so analysing "traffic flow" is an obvious connection--in the traffic engineering textbook I've used in grad school, many of the variables used to describe flow, capacity, etc. were the same as those used in my undergrad fluid dynamics class. I wish I had made the connection between the two topics much earlier...I probably would've done better in fluids class.
The merging example is another correct application of fluid dynamics and flow rate, except you need a lot more idiots. I believe it has to do with turbulence in the flow. If you have people merging over at random locations, it interrupts the steady flow at multiple points, causing the slowdown to propigate back upstream. However, if both lanes wait to merge at a single point (i.e. "zipper" merging), the upstream vehicles remain at constant speed and everything flows more smoothly. I believe this was actually studied a few years ago by a state DOT somewhere back east, that found when instructing drivers to merge at a specific point the delay was reduced by a significant amount.
You and flowmotion have given good, concise explanations for the phenomenon. You've made it easier to understand than anyone else ever did, at least for me.
The question then is why DOTs don't use more of their media budgets to explain it to the public? More cooperation between informed commuters might help to make construction zones safer for the workers, to say nothing of any improvement to commute x.
AbE: Sorry, I've been using 'x' as shorthand for both 'by' and 'times' for decades, long before the internet. I had a history teacher in high school who used it that way all the time on the chalkboard, and I picked up the habit. I do it without thinking. So in this case I was saying "commute times".
Quote from: roadfro on September 06, 2011, 05:41:57 AM
I've taken courses in traffic engineering that have dealt with signal timing and progression. The concept of "mandatory red" was never discussed. The whole objective of signal coordination is to keep traffic moving, so purposefully stopping platoons of traffic multiple times doesn't really make sense with that goal.
I think it's interesting that traffic engineering instruction still focuses on "keep the traffic moving" rather than pedestrian safety, speed limit enforcement, and so forth. "Mandatory Reds" are pretty obviously widely employed, so it must be something that's taught in the trades rather than in school.
Either way, Traffic Engineering in San Francisco must be so unique that the Engineers probably must frequently 'throw out the book' and figure out the best contextual solution. I've been looking at the City's bicycle lane plans, and there seems to be a lot of very good thought put into integrating bikes into the street network while still maintaining auto traffic. I'm sure a lot of local engineers have an instinct for what works based on their knowledge of local drivers and traffic behavior that can't be summed up in signal timing tables.
Now I'm feeling regret for dragging the thread totally off-topic. So, US101 in CA between SF and LA should have been included in the Interstate system ... I can't imagine the logic which would have excluded it.
Quote from: flowmotion on September 07, 2011, 02:13:02 AM
I think it's interesting that traffic engineering instruction still focuses on "keep the traffic moving"
that is the basic function of roads.
Quoterather than pedestrian safety
a secondary function, to be subjugated to the right of basic travel. if pedestrians want to travel on the right of way, they should learn to run at 35 mph.
Quotespeed limit enforcement
an arbitrary set of standards, without any sort of redeeming value. speed limits are the lowest common denominator of the bureaucrat - preventing the driving populace from going at reasonable speeds, for the sake of raising revenue.
Quote from: agentsteel53 on September 07, 2011, 02:45:19 AM
a secondary function, to be subjugated to the right of basic travel. if pedestrians want to travel on the right of way, they should learn to run at 35 mph.
Bullshit. There's no right to travel at 35 mph.
Quote from: NE2 on September 07, 2011, 03:04:57 AM
Bullshit. There's no right to travel at 35 mph.
it is an arbitrary number, but the fact is, that road design should allow for travel at velocities which are within the normal range of motor vehicles.
that is what roads are designed for.
Quote from: flowmotion on September 07, 2011, 02:13:02 AM
So, US101 in CA between SF and LA should have been included in the Interstate system ... I can't imagine the logic which would have excluded it.
It was submitted (in two segments - 101 from LA to SF, and then from the Golden Gate Bridge to Route 37) in the late 1940s proposals but rejected - I do wonder if the reasons for this not being added were ever written down somewhere.
Personally I do like the fact that you still have two major American cities connected directly by a US highway rather than an Interstate, though that's more a function of geographic circumstance than anything else. (And one could argue that when I-5W existed, that this was more of the case on the Interstate end, even if 5W only came within 5 miles of SF city limits.)
Quote from: agentsteel53 on September 07, 2011, 03:06:19 AM
Quote from: NE2 on September 07, 2011, 03:04:57 AM
Bullshit. There's no right to travel at 35 mph.
it is an arbitrary number, but the fact is, that road design should allow for travel at velocities which are within the normal range of motor vehicles.
that is what roads are designed for.
Maybe, but you speak of a right to travel at such velocities. There is none in the constitution or common law (the 'right to travel' comes from the latter).
The UN recently declared Internet access to be a human right (http://www.theatlanticwire.com/technology/2011/06/united-nations-wikileaks-internet-human-rights/38526/), yet you don't see that in anyone's Constitution. There are a lot of things that we consider human rights that aren't actually protected de jure.
Also consider the fact that Jake usually speaks sarcastically and exaggerates things for rhetorical purposes and you'll soon realize that this is a debate you would be foolish to spend much more time on.
Those commies at the UN would be more likely to declare jaywalking to be a human right. Fuck 'em.
Quote from: NE2 on September 07, 2011, 10:37:07 AM
Those commies at the UN would be more likely to declare jaywalking to be a human right. Fuck 'em.
I have a strict policy against sexual intercourse with communists. In fact, the only people who meet my standards of desirability are Ayn Rand and her evil twin Bearded Spock.
Quote from: NE2 on September 07, 2011, 10:37:07 AM
Those commies at the UN would be more likely to declare jaywalking to be a human right. Fuck 'em.
Jaywalking isn't a human right because it interferes with the human right to drive at 35 MPH.
Quote from: flowmotion on September 07, 2011, 02:13:02 AM
I think it's interesting that traffic engineering instruction still focuses on "keep the traffic moving" rather than pedestrian safety, speed limit enforcement, and so forth. "Mandatory Reds" are pretty obviously widely employed, so it must be something that's taught in the trades rather than in school.
It's more like traffic engineering focuses on "keeping all traffic moving safely and efficiently". The "all" encompasses vehicles, bicyclists and pedestrians, not just vehicles alone--although admittedly it has been only recently in the traffic community that more equal consideration has been given to multi-modal transport as opposed to singular focus on vehicles, and vehicle transport is still the predominant consideration. It's the actual design of the road and related traffic controls that traffic engineers concern themselves with--things like enforcement are left up to the police and public safety officials (but sometimes with input from the engineering side).
I would argue that "mandatory red" is not something widely employed, at least not consciously. Again, in the interest of keeping traffic moving, there is little reason why there would be a need to deliberately stop traffic if it is possible to keep it moving. If talking about coordinated signal systems, traffic moving much faster/slower than the assumed progression speed (typically at or near a posted speed limit) may find itself drifting outside the progression window, thus encountering more red lights and making it seem like being forced to stop.
Quote from: roadfro on September 08, 2011, 09:30:02 AMI would argue that "mandatory red" is not something widely employed, at least not consciously. Again, in the interest of keeping traffic moving, there is little reason why there would be a need to deliberately stop traffic if it is possible to keep it moving. If talking about coordinated signal systems, traffic moving much faster/slower than the assumed progression speed (typically at or near a posted speed limit) may find itself drifting outside the progression window, thus encountering more red lights and making it seem like being forced to stop.
Aren't there combinations of speed limit and signal spacing which render signal progression non-attainable at certain points within a district subject to traffic signal control? This could result in apparent "mandatory reds" along certain itineraries within that district.
Quote from: J N Winkler on September 08, 2011, 11:14:38 AM
Quote from: roadfro on September 08, 2011, 09:30:02 AMI would argue that "mandatory red" is not something widely employed, at least not consciously. Again, in the interest of keeping traffic moving, there is little reason why there would be a need to deliberately stop traffic if it is possible to keep it moving. If talking about coordinated signal systems, traffic moving much faster/slower than the assumed progression speed (typically at or near a posted speed limit) may find itself drifting outside the progression window, thus encountering more red lights and making it seem like being forced to stop.
Aren't there combinations of speed limit and signal spacing which render signal progression non-attainable at certain points within a district subject to traffic signal control? This could result in apparent "mandatory reds" along certain itineraries within that district.
Yes. Like any crosstown street in Manhattan (the avenues are coordinated, the cross streets, therefore, are not).
Mandatory reds are sometimes employed by traffic engineers to "regroup a platoon". Basically, if you coordinate well along a corridor, most traffic will never see a red for a while...this lets the platoon of vehicles spread out. Then you come to an intersection with a short green (lot of cross traffic), and the entire platoon can't fit through because it is too spread out. So rather than risk artificial congestion due to the platoon not making it through the signal, they time it a little out of sync to catch the front of the platoon just as it turns red which forces the platoon to re-group. Then when the signal turns green, those cars in the regrouped platoon can all get through.
Obviously, significant work needs to be done to ensure that the volumes and progression can support this, because its very easy to screw this up and make things worse.
Quote from: J N Winkler on September 08, 2011, 11:14:38 AM
Quote from: roadfro on September 08, 2011, 09:30:02 AMI would argue that "mandatory red" is not something widely employed, at least not consciously. Again, in the interest of keeping traffic moving, there is little reason why there would be a need to deliberately stop traffic if it is possible to keep it moving. If talking about coordinated signal systems, traffic moving much faster/slower than the assumed progression speed (typically at or near a posted speed limit) may find itself drifting outside the progression window, thus encountering more red lights and making it seem like being forced to stop.
Aren't there combinations of speed limit and signal spacing which render signal progression non-attainable at certain points within a district subject to traffic signal control? This could result in apparent "mandatory reds" along certain itineraries within that district.
If you're talking overall progression for a network of signalized intersections, then yes it is conceivable that there will be points in the network that progression will be much less than desired. This can depend on a number of factors which can include speed, spacing, movements (one-way vs. two-way, left turn control) and signal phases (protected left turns, etc.).
However, if you're just looking at the signal coordination of a single roadway, a decent progression window can be achieved for the entirety of the arterial. This is relatively easy to obtain, just by putting the start of coordinated signal phase the same for each intersection, then adjusting the offset that phase to account for the speed and distance between signals. Traffic analysis software such as PASSER II and Synchro can determine appropriate settings for a coordinated arterial relatively easily, with speed and turning counts used as minimal inputs.
Quote from: mtantillo on September 08, 2011, 12:33:29 PM
Mandatory reds are sometimes employed by traffic engineers to "regroup a platoon". Basically, if you coordinate well along a corridor, most traffic will never see a red for a while...this lets the platoon of vehicles spread out. Then you come to an intersection with a short green (lot of cross traffic), and the entire platoon can't fit through because it is too spread out. So rather than risk artificial congestion due to the platoon not making it through the signal, they time it a little out of sync to catch the front of the platoon just as it turns red which forces the platoon to re-group. Then when the signal turns green, those cars in the regrouped platoon can all get through.
Like I've said, I've never heard the term "mandatory red". The above example makes sense, but one has to wonder if there are other ways to achieve a similar purpose. I'm going to have to talk with my traffic engineering professor and consult some sources--I'm genuinely intrigued as to just how common this is. Although even the whole concept of coordinated signal timing and progression is still new to many jurisdictions...
Thanks for the linky. Interesting reading on the history.
Quote from: mtantillo on September 08, 2011, 12:33:29 PM
Mandatory reds are sometimes employed by traffic engineers to "regroup a platoon". Basically, if you coordinate well along a corridor, most traffic will never see a red for a while...this lets the platoon of vehicles spread out. Then you come to an intersection with a short green (lot of cross traffic), and the entire platoon can't fit through because it is too spread out. So rather than risk artificial congestion due to the platoon not making it through the signal, they time it a little out of sync to catch the front of the platoon just as it turns red which forces the platoon to re-group. Then when the signal turns green, those cars in the regrouped platoon can all get through.
Why does traffic need to be in platoons at all? When I'm driving, the last thing I want to be in is a platoon. I prefer to choose my own speed, not give that choice to the vehicle in front of me.
QuoteWhy does traffic need to be in platoons at all? When I'm driving, the last thing I want to be in is a platoon. I prefer to choose my own speed, not give that choice to the vehicle in front of me.
While I agree with you from a driving standpoint, it helps traffic at unsignalized cross streets/driveways turn- a steady stream of cars is harder to turn into than clumps with gaps
Quote from: deanej on September 09, 2011, 11:55:52 AM
Why does traffic need to be in platoons at all? When I'm driving, the last thing I want to be in is a platoon. I prefer to choose my own speed, not give that choice to the vehicle in front of me.
Coordinated signal timing is based on platoons. The idea is that subsequent signals are timed such that the platoon of vehicles departing the first signal at the onset of green will reach the next signal during green as a group, so the entire group can pass through multiple signals in a row without stopping. Vehicles that deviate too far from the travel speed of the platoon (i.e. the speed the signals are timed for) will eventually encounter a red signal by either arriving too soon at a light (traveling ahead of the group) or arriving too late (slowing behind the pack).
Outside of coordinated signal timing, there isn't much need to keep traffic in platoons. I'd say platoons in any other instance could be more harmful--hence why ramp meters exist.
However, some roads work much better than others at this. Take, for example, Telegraph Rd (US-24) in Michigan versus IL-59 in Will and DuPage Counties, Illinois. The absence of left turn signals along US-24, IMHO, makes these platoons more predictable and flow much better for miles on end than the over-signalization with dedicated left turn signals long IL-59.
Quote from: Brandon on September 09, 2011, 10:57:44 PM
However, some roads work much better than others at this. Take, for example, Telegraph Rd (US-24) in Michigan versus IL-59 in Will and DuPage Counties, Illinois. The absence of left turn signals along US-24, IMHO, makes these platoons more predictable and flow much better for miles on end than the over-signalization with dedicated left turn signals long IL-59.
In most of Oakland County, yes, even with the mandatory red at 15 Mile.
Once you get south of 696, the lights aren't synced as well.
<---Is glad that I-10 wasn't routed to follow Chef Menteur Highway (US 90). Parts of that road may be gone.
I bet Baton Rouge area leaders today wished that I-410 (would have roughly followed Airline Highway) was built now that I-10 and I-12 has heavy traffic today.
I think the state did a good job with most interstate routing.
Quote from: InterstateNG on September 09, 2011, 11:27:30 PM
Quote from: Brandon on September 09, 2011, 10:57:44 PM
However, some roads work much better than others at this. Take, for example, Telegraph Rd (US-24) in Michigan versus IL-59 in Will and DuPage Counties, Illinois. The absence of left turn signals along US-24, IMHO, makes these platoons more predictable and flow much better for miles on end than the over-signalization with dedicated left turn signals long IL-59.
In most of Oakland County, yes, even with the mandatory red at 15 Mile.
Once you get south of 696, the lights aren't synced as well.
Never had a problem with them between 696 ad 94. I usually find the mandatory red is at Ford Rd.