Traffic signals that back up traffic through previous intersections

[webny99]

Taking a macro-view of Rochester's east side and suburbs, something very interesting happens on the main eastbound arteries: there is chronic PM congestion at each road where it crosses Five Mile Line Road:

Starting from the north:
NY 404 routinely backs up through the previous light at Hatch Road (though an extended left-turn lane has helped).
NY 286 routinely backs up through two lights (over a mile) leading up to what has got to be the most poorly-designed, chronically congested and incapacitated intersection in the region, if not nationwide.
NY 441 backs up through the previous interchange on approach to the Four Corners of Penfield; there is simply too much volume passing through to be handled by anything short of a freeway, much less at a major cross street with no right turn lanes.


Where else does traffic back up through previous junctions (NOT due to close spacing.. minimum quarter-mile), and does it recur elsewhere along parallel corridors at the same spot? Or is it unique to a single road, due to capacity constraints?

[jeffandnicole]

I can name countless examples of this, but one example come to mind:  NJ 42, from Ganttown Road back thru 3 previous lights.  This is a PM Rush Hour issue, along with a Weekend Issue, mostly due to a short cycle of the lights here.

[abefroman329]

Tons in Chicagoland, thanks to the miles and miles of at-grade train tracks that also carry commuter trains.

And I realize I'm part of the problem when I block the intersection, but I'm just fed the fuck up with waiting until traffic past the intersection is clear enough for me to pull forward without blocking it, only to have someone turning right or left from the cross street pull in front of me.

[renegade]

Go to Ann Arbor, the capital of progressive red lights and useless protected lefts.  No one there can drive without a fucking arrow telling them which way to go, and it's impossible to go through town at at any time without waiting two to three minutes at a red ball because a green arrow is lit for oncoming, non-existing inbound traffic.  This happens at every signal, day or night, no matter which route you take.

You need to plan for about an hour to travel 12 miles.  At some intersections, you will wait through two or three full cycles at some intersections, which can take up to three minutes to get around to a 45-second green ball.

[Brandon]

Go to Ann Arbor, the capital of progressive red lights and useless protected lefts.  No one there can drive without a fucking arrow telling them which way to go, and it's impossible to go through town at at any time without waiting two to three minutes at a red ball because a green arrow is lit for oncoming, non-existing inbound traffic.  This happens at every signal, day or night, no matter which route you take.

You need to plan for about an hour to travel 12 miles.  At some intersections, you will wait through two or three full cycles at some intersections, which can take up to three minutes to get around to a 45-second green ball.

What did you expect?  It's Ann Arbor, aka Arrogant Asshole.

[hotdogPi]

Go to Ann Arbor, the capital of progressive red lights and useless protected lefts.  No one there can drive without a fucking arrow telling them which way to go, and it's impossible to go through town at at any time without waiting two to three minutes at a red ball because a green arrow is lit for oncoming, non-existing inbound traffic.  This happens at every signal, day or night, no matter which route you take.

You need to plan for about an hour to travel 12 miles.  At some intersections, you will wait through two or three full cycles at some intersections, which can take up to three minutes to get around to a 45-second green ball.

Ann Arbor? I thought the Detroit area, and to a lesser extent, all of Michigan, had the best signal progression in the country.

[odditude]

Common in Philadelphia on Broad St (PA 611) SB; traffic from the Vine St intersection backs up past Callowhill Ave, usually due to people trying to make the left turn onto the I-676 EB ramp (which is at the same intersection).

[jp the roadgeek]

Take I-84 Exit 39 to CT 4 during rush hour and head west on CT 4, and it is backed up almost a mile from CT 10 back onto the SR 508 ramps.  There is a choke point just past the light at the end of the ramp by the jughandle where two lanes merge together, and it is bumper to bumper after that around 2 sharp curves and a newer traffic light to get to CT 10.  The whole road is usually a mess all the way to Unionville, almost 5 miles from the ramp.

[sparker]

It's San Jose -- where do I start?  Any street parallel to an freeway commonly used for peak-hour commutes generally exhibits this phenomenon:  I-880 and its "overflow" parallel streets -- Old Oakland Road (literally the pre-freeway SSR 17) to the east and McCarthy Ave. to the west back up -- in both directions every afternoon after about 3:30; the backup often extends for blocks through successive signals.  The most common culprits for the backup: Brokaw Road and Montague Expressway, both crossing I-880 with full interchanges.   Farther to the southwest, both Stevens Creek Blvd. (to the north) and Moorpark Avenue (to the south) exhibit the same phenomenon vis-a-vis I-280 between central San Jose and Cupertino. The backup here commonly occurs between Bascom Avenue and Winchester Blvd, both of which flank I-880/CA 17; the latter has its own backup issues, exacerbated by the Valley Fair shopping center just NW of the 280/880/17 interchange.  Essentially the quartet of streets acts like an ersatz "volleyball" network, often used for that purpose when the direct freeway ramps are themselves at a standstill.

But other multi-signal backup offending streets exist -- including just about any N-S street with an interchange at US 101.  North First Street in San Jose, the Trimble/De La Cruz continuum near SJO (aka Mineta Airport), Great American Parkway (anecdotally the worst offender), Lawrence Expressway, and pretty much any crossing street north to Palo Alto during the morning and afternoon "rush".  Since the major employment centers in the region are lined up on both sides of US 101, this is hardly surprising -- but it's gotten so bad that almost any arterial in the area is gridlocked between 6:30 and 9 in the morning and 3:30 and 7 in the evening. 

Unless one is a senior IT/programming person making $300K+/year, the solution of living close to work just doesn't apply; new 1700sf "infill" townhouses along the Caltrain rail corridor (functionally the dividing line between the "Silicon Valley" employment centers and housing locations) are coming on line at an average of $1.4M.  A few can afford to live here; the rest commute from the Fremont area, which averages about 15-20% lower housing cost, or as far away as Brentwood or the Central Valley, where 40-70% cost differences are available.  But as long as there are higher-paying jobs in the region relative to elsewhere, the traffic will persist.         

[Beltway]

Countless examples, it's called "intersection failure", when it takes multiple signal cycles to get the queue thru the intersection.

[renegade]

Go to Ann Arbor, the capital of progressive red lights and useless protected lefts.  No one there can drive without a fucking arrow telling them which way to go, and it's impossible to go through town at at any time without waiting two to three minutes at a red ball because a green arrow is lit for oncoming, non-existing inbound traffic.  This happens at every signal, day or night, no matter which route you take.

You need to plan for about an hour to travel 12 miles.  At some intersections, you will wait through two or three full cycles at some intersections, which can take up to three minutes to get around to a 45-second green ball.

Ann Arbor? I thought the Detroit area, and to a lesser extent, all of Michigan, had the best signal progression in the country.

Yeah, the best signal progression ... if you want to be stuck in traffic.Classic example is Washtenaw Avenue from Carpenter west to Huron Parkway.  The offramp from southbound US-23 to westbound Washtenaw is signalized.  Washtenaw is made to wait, as the offramp has priority, for some reason.  Fifty yards wast of that signal is the signalized entrance to Arborland, where westbound traffic is held for a protected left for eastbound Washtenaw, so traffic from Carpenter, Washtenaw and the expressway are all trapped trapped there.  One block west is the exit from Arborland, signalized with protected lefts, which causes more backup into the previous two intersections,which are in turn trapped because the signal at Huron Parkway, one-half-mile west, does not stay green long enough for any traffic to clear, because of the proteced lefts.  In this scenario, traffic is brought to gridlock because of the left-turn arrows.  I am not sure why flashing yellow arrows are not used at any of these intersections, but I believe if they were implemented, traffic in the area would have a reasonable chance at flowing.

Full disclosure:  Not a traffic engineer, but I'd probably do a better job than the ones around here.   

[1995hoo]

Tons in Chicagoland, thanks to the miles and miles of at-grade train tracks that also carry commuter trains.

And I realize I'm part of the problem when I block the intersection, but I'm just fed the fuck up with waiting until traffic past the intersection is clear enough for me to pull forward without blocking it, only to have someone turning right or left from the cross street pull in front of me.

Around here, I've sometimes had people behind me decide my refusal to block the box is an invitation for them to cut in front of me so as to block it. Cabbies and Uber drivers who think the turn lane is their shortcut lane to cut the line are among the most obnoxious about it.

[abefroman329]

Tons in Chicagoland, thanks to the miles and miles of at-grade train tracks that also carry commuter trains.

And I realize I'm part of the problem when I block the intersection, but I'm just fed the fuck up with waiting until traffic past the intersection is clear enough for me to pull forward without blocking it, only to have someone turning right or left from the cross street pull in front of me.

Around here, I've sometimes had people behind me decide my refusal to block the box is an invitation for them to cut in front of me so as to block it. Cabbies and Uber drivers who think the turn lane is their shortcut lane to cut the line are among the most obnoxious about it.

Oh yes, that used to happen to me in DC too.

[Hurricane Rex]

Portland there are many examples, so I'll just stick with Sherwood intersections. The 99W and Tualatin Sherwood Road intersection can get bad on 99, but since signals are 1/3 of a mile apart, it rarely affects other signals. The side roads, Roy Rogers can be backed up for a mile (one signal) and Tualatin Sherwood is backed up also for a mile (3-4 signals, depending on traffic).

LG-TP260

[vdeane]

Wolf Road has them.  Southbound, the one at Colonie Center sometimes backs up past NYSDOT, particularly in the Christmas shopping season (with Toys R Us gone, traffic has been a little better, so this might not happen as often this year) or if someone decides to load their bike onto the rack on the bus at the stop right at the light, which can stop traffic for an entire cycle.  Sometimes the light at Central Avenue (NY 5) will back up too (Central itself has this at just about every intersection).  Northbound, the ending light at Albany Shaker Rd/I-87 north does this all the time, as does Albany Shaker Road on either side of I-87, and it can end up going all the way down to Sand Creek Road or NYSDOT if enough people are trying to bypass the Northway.  Thankfully, the light just south of Albany Shaker (the ramp from I-87) is going away when the flyover is built.

I've also seen this on Wade Road at NY 7; if there are enough shoppers, or if something is backing up traffic heading to I-87 north more than usual, it can back up through Forts Ferry Road.

[US 89]

I can think of many, many examples, but one that sticks out for me is 500 South in Salt Lake City. It's part of the only major one-way pair in the city, so theoretically it should be timed well. Unfortunately, the signal at Main Street has a light rail track, which keeps the signal red for a much longer time than would otherwise be needed. As a result, 500 South will back up several blocks. Normally it backs up to around 300 East, but I've seen it back up to 5th before. And people are terrible at not blocking the box at those intersections.

The Main Street signal usually screws up the progression enough that you wind up stopping for the red light at West Temple. After that, it's usually green for the rest of the way to I-15.

[RobbieL2415]

Ummm... any intersection in New York City.

Funny though, because in less trafficked areas the lights are STILL timed instead of using pre-emption. So you end up waiting for no one a majority of the time.

[kurumi]

Glastonbury, CT, has a new roundabout at Hebron Ave (old CT 94) and New London Turnpike (old CT 2, but modified alignment) that replaced a traffic signal. Another roundabout is going in at House St. Reason for both: pushback from the state -- studies showing that traffic signals there would back traffic up to the CT 2 interchange and the state-maintained (94) part of Hebron Ave.

[jakeroot]

Oh god. These are everywhere.

In Tacoma, one of the worst setups is S Steele St, between S 37 St and S 38 St. WB 37 St, to SB Steele, to EB 38 St is a very common maneuver, but the signals aren't always timed well, and left-turning traffic can end up blocking the 37 St/Steele St intersection quite often: https://goo.gl/jqxmKq (both intersections feature some split phasing).

[plain]

Very common as pretty much everyone has stated. Basically the main reason for the sign "DO NOT BLOCK THE BOX" or something similar.

[Bruce]

Mercer Street and a lot of the freeway-bound streets in downtown Seattle suffer from this due to their long cycles, lack of box-blocking enforcement, and haphazard "improvements" that just push bottlenecks around. It's just as bad as it was before the street reconstruction (which made it into a stroad that's extremely hard to cross).

[webny99]

Countless examples, it's called "intersection failure", when it takes multiple signal cycles to get the queue thru the intersection.

Well, that's where things get interesting. Yes, sometimes it is an intersection failure, which is basically what I call a timing failure. When volumes aren't that high and there's a backup, you know it's a problem with the timing/green space allocation.

But sometimes it is pure congestion that does it, and additional green space won't help; what's needed is additional lanes/turn lanes through the intersection. This is a classic example; note the worn-down shoulder from heavy use by through traffic. Bad timing is not the issue; in fact, the timing is perfectly - down to the second - in sync with other lights on the corridor. And no more green space can possibly be allocated to Atlantic Ave, since Five Mile Line Road also has delays of 2+ light cycles at peak times.

[webny99]

These are everywhere.

Very common as pretty much everyone has stated.

Yeah, I'm getting that vibe, but what I'm interested in is the intersection that is causing the problem, if it's possible to pinpoint.

[ftballfan]

Go to Ann Arbor, the capital of progressive red lights and useless protected lefts.  No one there can drive without a fucking arrow telling them which way to go, and it's impossible to go through town at at any time without waiting two to three minutes at a red ball because a green arrow is lit for oncoming, non-existing inbound traffic.  This happens at every signal, day or night, no matter which route you take.

You need to plan for about an hour to travel 12 miles.  At some intersections, you will wait through two or three full cycles at some intersections, which can take up to three minutes to get around to a 45-second green ball.

I lived in Ypsilanti for a year and the Huron Rd/Whittaker Rd/Huron River Dr light irritated me as SB Huron -> EB Huron River sometimes had to go through two or three light cycles to be able to complete that movement (and it's one of the busier movements at that particular intersection).

Speaking of Ann Arbor, the worst traffic jam had to be when I-94 at US-23 was closed due to an accident, diverting everyone onto side roads such as Eisenhower, Packard, and Ellsworth (the latter only being two lanes west of Platt). It took me at least 15 minutes to get from State to Platt along Ellsworth.

[tradephoric]

Ann Arbor? I thought the Detroit area, and to a lesser extent, all of Michigan, had the best signal progression in the country.

Good signal progression in the Detroit area is limited to Median u-turn corridors.  The fact is Ann Arbor doesn't have many Michigan left intersections and are plagued by poor signal progression like any other city.