Bad signal sequencing at interchanges by WISDOT

[peterj920]

There are 2 interchanges along WIS 172 (CTH GV, Webster Ave) that have illogical signal sequencing and it's causing traffic backups.  One off ramp gets a green light at the ramp terminal, and a green light with a green left arrow, even though no one wants to turn left to go back onto the freeway.  Even with that, the light at the opposite intersection turns red rapidly.  Then, the same sequence is used for the opposing off ramp, and cars are turning left onto Wis 172 because they've been waiting at a red light for the opposing ramp traffic.  I don't understand what the logic is for a left turn arrow to be up while traffic is turning off of the off ramp.  I do notice that the signals on I-41 on the west side of Green Bay is set up more logically by giving a green light to one of the ramp terminals and green to the mainline traffic on the opposing side of the freeway.  About the time that traffic on the mainline street catches up to the red light at the off ramp, the light turns green with a left turn arrow, which makes way more sense.  I hope I'm not confusing anyone but does anyone know the logic behind giving left turn arrows to traffic coming off of a freeway to traffic that doesn't need to turn left to go back onto the freeway?  The more logical signal sequencing used on I-41 should be used at every interchange, so why are they using the bad sequencing at other interchanges? 

[The Ghostbuster]

Send an email to WISDOT about this, and let us know if they respond and/or if they fix the problem.

[Roadguy]

There are 2 interchanges along WIS 172 (CTH GV, Webster Ave) that have illogical signal sequencing and it's causing traffic backups.  One off ramp gets a green light at the ramp terminal, and a green light with a green left arrow, even though no one wants to turn left to go back onto the freeway.  Even with that, the light at the opposite intersection turns red rapidly.  Then, the same sequence is used for the opposing off ramp, and cars are turning left onto Wis 172 because they've been waiting at a red light for the opposing ramp traffic.  I don't understand what the logic is for a left turn arrow to be up while traffic is turning off of the off ramp.  I do notice that the signals on I-41 on the west side of Green Bay is set up more logically by giving a green light to one of the ramp terminals and green to the mainline traffic on the opposing side of the freeway.  About the time that traffic on the mainline street catches up to the red light at the off ramp, the light turns green with a left turn arrow, which makes way more sense.  I hope I'm not confusing anyone but does anyone know the logic behind giving left turn arrows to traffic coming off of a freeway to traffic that doesn't need to turn left to go back onto the freeway?  The more logical signal sequencing used on I-41 should be used at every interchange, so why are they using the bad sequencing at other interchanges?

First I laughed a bit at this and want to ask, what signals on I-41 on the west side since they almost all have been replaced by roundabouts? But I assume you are referring to Lombardi, Oneida, and Velp.  Since Velp has a ramp closed and Oneida is under construction down to one lane they are not really good examples.  Lombardi is a good example but with dual lefts on WB to SB and EB to NB having so few left turns it makes it easy to coordinate the two lights at the ramp terminals.

The reason why 172 has the sequencing it does at Webster and GV is the fact there is virtually no left turn storage since the turn lanes are so short.  On Webster it's the SB left to EB 172 and GV the NB left to WB 172.  As person who has driven GV frequently, I see why they do this (especially at GV).  When the off ramp turns green for EB 172 to NB GV at the EB 172 ramp terminal, they turn on the green left turn light on NB GV at the WB 172 ramp terminal to clear the backup of left turning vehicles and give the vehicles turning left from EB 172 to NB GV free flow through the intersection.  Without this phasing, the left lane would be blocked by left turning vehicles and WisDOT does not want to risk left turning vehicles blocking lanes.  This sequencing is used for both interchanges and the main reason is to try to minimize left turning traffic from blocking the left lane.

This signal timing sequencing works well when interchanges have a lot of turning traffic and lower through traffic.  But now at GV and Webster there is more through traffic then there use to be and that is when this coordination scenario starts to fall apart at particularly when heavier volumes hit at rush hour.

If you think it is an issue, contact WisDOT.  Unless they get complaints or drive through there frequently, they are not going to realize it is a problem unless it's reported.

I wanted to have a long rant in this post about WisDOT and signal timing    but I refrained myself from doing so so I am giving myself a round of applause 

[peterj920]

Oneida st and Velp Ave were coordinated the same way before the construction.  Wis 29 before roundabouts were installed was sequenced the same way.  I should also add that Mason and I-43 is also sequenced a lot better than the interchanges on 172.  I drive Webster Ave almost every day and I've started going straight across 172, making a U turn by Heritage Hill, then turning right onto 172 west.  In the morning, traffic in the left lane wanting to go west on 172 backs up to Broadview, while hardly any traffic goes north on Webster.  Traffic moved a lot better on the I-41 signals before/after construction than the signals on 172.  Wis 96/I-41 used to be coordinated like the signals on 172, but are now sequenced like the signals on the west side of Green Bay and the interchange operates smoother, although it's a very busy interchange.  I'm just tired of turning south on GV from 172 and seeing a green light that immediately turns red on the other side of the freeway and seeing massive backups on Webster Ave.  I know there's a lot of traffic wanting to go west on 172, but I think the problem can be alleviated a little by re sequencing the lights. 

[SSOWorld]

WIS-52/Stewart Ave has a coordination problem too.  Between 17th and 18th ave the two often are out of sequence - even after the rebuild.

[peterj920]

The signals at Wis 172/Webster Ave that inspired me to start this thread are going to be replaced starting Thursday.  There are message boards at all 4 directions announcing the project and to expect delays.  It will be interesting to see what the new signals will look like and if any lane configurations will change.  The straight only lane heading east on the Webster ramp should allow left turns also, that would alleviate some backups.  Hopefully the new signals come with better sequencing to relieve congestion. 

[peterj920]

The signals were replaced at WIS 172/Webster Ave, and the sequencing is a lot better.  I don't think the traffic signals had to be completely replaced to fix the problem, but traffic is operating a lot smoother now that the sequencing is better.  The trombones were replaced with monotubes, and there are now flashing left turn arrows on Webster.  There is no longer a green arrow for traffic that is coming from 172 like there was in the past.  Midway through the sequence where traffic from the Wis 172 east off ramp has a green light, North Webster traffic has a green at the first traffic signal.  When traffic crosses the bridge, the signal is sequenced to change the signal to green with a green left turn arrow for northbound traffic.  The sequencing makes a lot more sense, and hopefully WISDOT can sequence the Wis 172/ County GV the same way.  Tomorrow morning will be the real test during morning rush hour.  I was going straight across 172, making a U turn and turning right onto 172 west because the left lane is usually backed up by a block in the morning.  The new sequencing should cut those backups down.