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Old 05-05-2014, 01:56 PM
 
Location: Whereever we have our RV parked
8,761 posts, read 7,689,871 times
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I've wondered about this for years, so I figured this was a good place to find an answer. In subdivisions built in the last 40 years, I find that sometimes, they don't lay out the streets so that you can get around conveniently in your neighborhood. Lubbock has nice wide main streets laid out in a very simple grid pattern, which is great for traffic flow. However, sometimes, just trying to get from one neighborhood to another is a bother, because they haven't laid out all the streets on a grid. The result is that sometimes, even though you may only have to travel a block or two, you can't take the side streets. You have to get onto the main thoroughfares, to just travel a few blocks. To me this just adds to congestion on the main streets and its a big gas waster, since you have to travel farther and sometimes sit at a stoplight. Why do they do this? It makes no sense.

This kind of pattern also discourages cycling to get where you want to go. Nobody I know with any sense wants to ride a bicycle on a six lane street with traffic going 40-50 MPH.
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Old 05-05-2014, 04:42 PM
 
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I think they have it laid out that way to prevent heavy traffic from running through a neighborhood. In my city some streets have been broken apart to discourage traffic in quiet neighborhoods.
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Old 05-05-2014, 09:56 PM
 
Location: Denver
14,151 posts, read 19,745,723 times
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Quote:
Originally Posted by augiedogie View Post
I've wondered about this for years, so I figured this was a good place to find an answer. In subdivisions built in the last 40 years, I find that sometimes, they don't lay out the streets so that you can get around conveniently in your neighborhood. Lubbock has nice wide main streets laid out in a very simple grid pattern, which is great for traffic flow. However, sometimes, just trying to get from one neighborhood to another is a bother, because they haven't laid out all the streets on a grid. The result is that sometimes, even though you may only have to travel a block or two, you can't take the side streets. You have to get onto the main thoroughfares, to just travel a few blocks. To me this just adds to congestion on the main streets and its a big gas waster, since you have to travel farther and sometimes sit at a stoplight. Why do they do this? It makes no sense.

This kind of pattern also discourages cycling to get where you want to go. Nobody I know with any sense wants to ride a bicycle on a six lane street with traffic going 40-50 MPH.
Because people would rather a moderately quieter neighborhood than to ease congestion for an entire city. Some people think simply widening major roads will ease congestion, but it doesn't. Developers keep building that crap and people keep signing purchase agreements like sheep.
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Old 05-05-2014, 11:04 PM
 
Location: Seattle, WA
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Street grids also slow down traffic by increasing the amount of stop lights. It's better to close streets off that way you keep residential neighborhoods quiet and decrease traffic lights.
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Old 05-06-2014, 04:48 PM
 
Location: Oakland, CA
27,164 posts, read 29,645,043 times
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Quote:
Originally Posted by GatsbyGatz View Post
Street grids also slow down traffic by increasing the amount of stop lights. It's better to close streets off that way you keep residential neighborhoods quiet and decrease traffic lights.

Actually street grids are much faster, they allow multiple pathways to your destination. With only one street, unless you keep expanding the lanes, it will meet its congestion point, and no one with have alternatives.

I just started a book called "Dead End" that came out a few weeks ago about how suburbia came to be. It is really interesting.

The lack of a grid, was invented by the real estate developers to cut down the costs or road infrastructure.

Much of our road design has one core priciniple: keep car traffic moving fast. We have classes of roads:
Types of road - Wikipedia, the free encyclopedia

And the road types influence the design and the road speed.
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Old 05-07-2014, 06:58 PM
 
Location: Maui County, HI
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They're intentionally designed that way to reduce traffic through the neighborhoods. There is a way to create neighborhoods that are walkable and bikeable but without through traffic-- bike/foot paths connecting blocks
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Old 05-07-2014, 08:34 PM
 
Location: Valdosta (Atlanta Native)
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Originally Posted by winkosmosis View Post
They're intentionally designed that way to reduce traffic through the neighborhoods. There is a way to create neighborhoods that are walkable and bikeable but without through traffic-- bike/foot paths connecting blocks
Actually this is what they're doing in one Atlanta suburb.
City of Morrow, Georgia
https://www.google.com/maps/place/Mo...487844bd?hl=en
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Old 05-09-2014, 06:40 AM
 
Location: Whereever we have our RV parked
8,761 posts, read 7,689,871 times
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Demonta: This is much the way the streets look here in Lubbock, which is great. What they've left out in some cases, however, is the connections so that you don't so often get on the main streets to get to another street less than a block away.
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Old 05-09-2014, 08:56 AM
 
409 posts, read 388,635 times
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Quote:
Originally Posted by GatsbyGatz View Post
Street grids also slow down traffic by increasing the amount of stop lights. It's better to close streets off that way you keep residential neighborhoods quiet and decrease traffic lights.
The problem with non-grids is they lead to inconsistently spaced traffic signals. You will never see a time-distance diagram like this on a major arterial in Atlanta or Boston. Basically, more traffic signals don't slow drivers down if great two-way progression is achieved.
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Old 05-09-2014, 02:20 PM
 
409 posts, read 388,635 times
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^The above time-distance shows coordination for signals spaced 1/2 mile apart. There are two main reasons why the above time-distance isn't practical in the real world at this spacing.

#1. There is an associated "lost time" every time a traffic signal changes phases. Even for a simple 2-phase signal, an 80 second cycle would result in roughly 15% lost time each cycle. As the number of phases increase, the lost time per cycle increases even more. Essentially, an 80 second cycle length is too short to maximize the throughput of an intersection, even at a simple 2-phase signal.

#2. Pedestrian crossing lengths. Assume you want to maintain a 50/50 split at a simple 2-phase signal. If a pedestrian crossing is longer than 115 feet, a pedestrian actuation will cause the signal to run long (assuming the MUTCD standards are being followed). Pedestrian actuation can cause havoc when the peds don't fit into the desired vehicle phase time.

To achieve good 2-way progression along a high speed arterial (45 mph or higher), signals really need to be spaced farther apart. Signals spaced 3/4 to 1 mile apart are much easier to provide good 2-way progression. Unfortunately, signals spaced 1/4 to a 1/2 mile apart are much more common along a suburban arterial as every school, residential drive, and shopping center request a traffic signal to be installed. You end up with a minefield of traffic signals, where drivers are inevitably going to get stopped by multiple red lights.
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