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Old November 23rd, 2017, 02:58 PM   #12441
sotonsi
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Quote:
Originally Posted by SounderBruce View Post
A perfect depiction of induced demand.
Or, much more likely, suppressed demand becoming unsuppressed - the extra capacity hasn't created more demand, but rather supplied more of it.

This isn't new demand (which is created by new routes opening up or developments on existing routes) that's induced by the increase in capacity, but demand that was already there and unfulfilled due to not enough capacity before the widening.

Adding more capacity somewhere where demand is saturated means more people can make that journey at a similar level of congestion. Congestion is self-regulating and no one wants to sit in traffic or be rammed up against several strangers on transit if they can help it.

Inner London's traffic speeds haven't changed for decades - with the increase of private cars and the building of new roads about 50 years ago they didn't change, and with the pushing people out of space-taking cars and onto buses and bikes of the last 15 years, they didn't change either. The saturation of supply by the demand means the system is at equilibrium when it comes to speed. The same is true of the Sepulveda corridor where any capacity increase or efficiency in using that capacity will just fill up to reach the point of equilibrium.
Quote:
"The 405" (bleh) just got expanded at the cost of $1 billion and really doesn't look any different during peak periods.
But a whole other lane of traffic can now travel instead of not travelling. If you are going to spend $1 billion dollars on something, you'd better be doing something that is utilised by people.

When new transit schemes get busy due to people using them, that's (rightly) treated as a success.
When new road schemes get busy due to people using them, that's (wrongly) treated as a failure.
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The Sepulveda Pass Metro line can't come soon enough.
Absolutely, for the exact same reasons as to why widening the 405 meant it filled up - it's a corridor without anywhere near enough capacity for the demand. Adding other modes is a good thing, but too many people see transit and roads as either/or not both/and.
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Old November 23rd, 2017, 03:12 PM   #12442
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Quote:
Originally Posted by SounderBruce View Post
A perfect depiction of induced demand. "The 405" (bleh) just got expanded at the cost of $1 billion and really doesn't look any different during peak periods.

The Sepulveda Pass Metro line can't come soon enough.
Holiday weekend traffic isn't really an example of induced demand.

Los Angeles County has a pretty significant amount of transportation demand management measures in place. These measures include carpool lanes, tolled express lanes, and a growing light rail network. Transportation demand management works on the assumption that not everyone needs to use the highway network at the same time. It's somewhat analogous to how a bank can lend out more money than it has deposited. A bank can do so on the assumption that not everyone will need access to their money at one time.

The problem with holidays is that lots of people do need access to the highway network at once (or at least want access to the highway network badly enough to be willing to endure the experience). They are making trips that aren't within their typical daily routine, and the TDM measures that try to manage highway capacity aren't very useful.
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Old November 23rd, 2017, 03:24 PM   #12443
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They should've built four or even six tolled express lanes across the Sepulveda Pass. Not just an overpriced family lane.
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Old November 23rd, 2017, 05:08 PM   #12444
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They should've built four or even six tolled express lanes across the Sepulveda Pass. Not just an overpriced family lane.
^ I agree. The 405 would be a fantastic facility for an express tolled facility. A four lane tolled facility was considered during the design, however from what I found online, it was always proposed to be a four-lane elevated tollway running through the median. Presumably, what ended up being designed didn't preclude such a tollway in the future.

See Alternative 4 and 5 on page 33 of the below report:
http://www.dot.ca.gov/d7/env-docs/do...ass_IR_EIS.pdf
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Old November 23rd, 2017, 09:38 PM   #12445
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Originally Posted by sotonsi View Post
Adding other modes is a good thing, but too many people see transit and roads as either/or not both/and.
Couldn’t agree more. We need both.

Transit gives us an option to driving. Something that is extremely important. If there’s an accident on the 405, right now you’re screwed, along with tens of thousands of other people. But with a transit line, there’s at least another option.

Up here in Wine Country after the fires, this transit option has played a critical role in the disaster. Our recently opened train line (SMART) provided free emergency service immediately after and continues to give people options now that traffic here has significantly worsened due to the fact that 1000’s who have lost their homes now live further away and are on the freeway more. My wife’s evening commute has gone from 40 minutes to 1 hour and 15 min on Tuesday (she took SMART the next day).

Back to topic..

Yes, we need freeways and they need to be expanded wisely. We also need to invest heavily in transit options. As one the busiest freeways in the country, the 405 could probably benefit from a tolled facility. There’s still a good chance though that you’ll encounter traffic somewhere along your route. So a rapid transit line is needed there ASAP. Right now, people have one option, and that is sitting in traffic. The more options the better.

I’ve always wondered what our cities would/will look like with teleportation when all this infrastructure isn’t needed.
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Old November 23rd, 2017, 09:52 PM   #12446
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Apart from converting left shoulders into carpool lanes, there hasn't been much freeway upgrades in the Los Angeles area since the last freeways opened during the 1970s. The population has grown by 7-9 milion people since. Think of adding the population of the Dallas-Fort Worth area to an already overburdened road system. It's no wonder you see traffic counts around 300,000 on just 10 lanes with congestion occurring 10-12 hours per day. It's clear that a single carpool lane - even if it costs $ 1 billion - wouldn't significantly alleviate congestion. However Los Angeles has spent billions on rail that has not alleviated congestion either. Reportedly the transit share is even lower today than it was before the rail transit system was built, due to massive cuts to bus services.
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Old November 26th, 2017, 06:36 AM   #12448
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The High Five - Dallas, TX
  • I-635 (LBJ Fwy) @ US 75 (Central Expy)
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  • HOV bridge - 140' above Central Expy


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Old November 26th, 2017, 07:16 AM   #12449
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Quote:
Originally Posted by sonysnob View Post
I-405, Sepulveda Pass, Los Angeles California

I used to live off Skirball in that pass. How I do NOT miss that section of the 405

Lived through the widening too. What a clusterf**k that project was.

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Old November 28th, 2017, 03:31 PM   #12450
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Conceptual interchange for I-35E @ U.S. 287 in Waxahachie, TX.

Would be DFW's southernmost interchange.

Unfortunately this is not even in the plans.
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Old November 28th, 2017, 06:09 PM   #12451
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Unfortunately this is not even in the plans.
Yeah, I agree. I just drove through there and the only thing changing is the that I-35E are getting new wider bridges over 287 as it is expanded to 3 three lanes each direction.
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Old November 28th, 2017, 08:34 PM   #12452
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Yeah, I agree. I just drove through there and the only thing changing is the that I-35E are getting new wider bridges over 287 as it is expanded to 3 three lanes each direction.
Well, the city of Waxahachie itself confirmed this to be false.
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Old November 28th, 2017, 09:38 PM   #12453
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California

I was browsing through the California AADT data and found some unusual / impossible figures for CA-60.

According to this sheet, the 10 lanes (8 GP and 2 HOV) would carry 461,000 vehicles per day on average. And traffic volumes would jump +160,000 from just two exits (not being freeway-to-freeway interchanges).

I think this is a typo. 461,000 (and a peak month of 483,000) is really not possible on just 10 lanes. To compare, the 401 through Toronto carries around 400,000 on 16 lanes and is heavily congested. A 10 lane freeway typically becomes congested at over 200,000 - 220,000 vehicles per day, depending on truck share, which is likely high on CA-60 given that it connects major industrial areas.



If we exclude this stretch of CA-60, the busiest segments in California would be;

1) I-405 at CA-22: 377,600
2) I-405 at Seal Beach: 370,100
3) CA-60 at Grand Avenue: 370,000
4) I-5 at Santa Ana Main Street: 366,000
5) I-5 at Santa Ana 17th Street; 362,500

These figures are more in line with older AADT figures. This CA-60 segment is on the CA-57 concurrency in Diamond Bar, which has 12 lanes and traffic from CA-57 mixes with CA-60 for a few miles, which explains the high volume.

Still, 370,000 on 12 lanes is also an extreme value. This means that section is likely congested through most of the day.

All AADT values in Los Angeles are borderline absurd with some sections handling 300,000 - 330,000 on just 10 lanes (8 GP and 2 HOV). In other parts of the U.S. and the world, such volumes are 1 ) rare, and 2) usually found on wider freeways (think of 14-16 lanes and still congested).
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Old November 28th, 2017, 10:17 PM   #12454
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401's 16-lanes are a bit overrated. The number of lanes go up and down constantly between every exit. At its widest point it may be 16 lanes, but maybe for a km or 2.
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Old November 29th, 2017, 01:45 AM   #12455
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it is 18 through lanes wide from the 427 to the 410. The busiest part, between the 400 and Weston Road, is 15 through lanes with a few more auxiliary lanes.

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Old November 29th, 2017, 02:30 AM   #12456
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Quote:
Originally Posted by ChrisZwolle View Post
I think this is a typo. 461,000 (and a peak month of 483,000) is really not possible on just 10 lanes. To compare, the 401 through Toronto carries around 400,000 on 16 lanes and is heavily congested.
Highest AADT on 401 in Toronto was 440,000 almost a decade back. It has worsened since.

Even 427 has recently crossed 400,000 in Toronto with just 14 lanes in that section. Having express collector on 427 would have helped a bit but it does get quite congested.

Quote:
Originally Posted by siamu maharaj View Post
401's 16-lanes are a bit overrated. The number of lanes go up and down constantly between every exit. At its widest point it may be 16 lanes, but maybe for a km or 2.
It is 18 lanes at the widest point but it has a collector express system with a minimum of 12 lanes for almost 70 km. It varies between 12 and 18 lanes in this distance. Because it is a collector express system, it has a higher capacity per lane since weaving is limited and it has 8 shoulder lanes (which, sometimes, are not full lane wide) which help in case of breakdowns.
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Old November 29th, 2017, 02:33 AM   #12457
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except for that nasty 8-lane section between the two 427's
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Old November 29th, 2017, 02:40 AM   #12458
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AADT of the 401 peaks at 416,500 right now. Summer average daily traffic sits at 458,100. The highest traffic count recorded was 492,900 for Summer Weekday traffic in the summer of 2004.. but has declined a bit since.
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Old November 29th, 2017, 03:22 AM   #12459
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What made AADT decline after 2004? Highway 407?
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Old November 29th, 2017, 06:10 AM   #12460
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Quote:
Originally Posted by SounderBruce View Post
A perfect depiction of induced demand. "The 405" (bleh) just got expanded at the cost of $1 billion and really doesn't look any different during peak periods.

The Sepulveda Pass Metro line can't come soon enough.
No this is holiday traffic in the 2nd largest city in the US. Most of 405 down there has been developed and very congested for decades so hardly induced demand. 405 here in the Seattle metro badly needs to be upgraded to the same capacity. It's pretty bad that we rank up closer to LA with traffic congestion but they have 3 times the amount of people. They also have better mass transit.

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