Urban planning community

+ Reply to thread
Results 1 to 13 of 13

Thread: Vehicle capacity analysis as a measure of quality of life?

  1. #1

    Vehicle capacity analysis as a measure of quality of life?

    I'm wondering what transportation planners -- and planners, generally -- think of using vehicle capacity analysis as a determinant of neighborhood quality of life. It seems to me that the two are related -- the more traffic, the more noise/vibration/congestion and therefore a perception of decreased neighborhood quality -- but that the analysis lacks quantitative metrics. It's more art than science, I'm guessing, but that's where y'all come in.

    Obviously, numerous factors would play into the equation: local traffic habits/police enforcement/urban design, and others. I'm thinking not of two lane roads in a rural area but rather of a fairly densely developed urban grid.

    What sayeth the Trobbing BrianTM?

  2. #2
    Cyburbian ColoGI's avatar
    Registered
    Jul 2009
    Location
    Colo Front Range
    Posts
    2,395
    Quote Originally posted by Gedunker;614793
    I'm wondering what transportation planners -- and planners, generally -- think of using vehicle capacity analysis as a determinant of neighborhood quality of life. It seems to me that the two are related -- the more traffic, the more noise/vibration/congestion and therefore a perception of decreased neighborhood quality -- but that the analysis lacks quantitative metrics. It's more art than science, I'm guessing, but that's where y'all come in.

    Obviously, numerous factors would play into the equation: local traffic habits/police enforcement/urban design, and others. I'm thinking not of two lane roads in a rural area but rather of a fairly densely developed urban grid.

    What sayeth the Trobbing BrianTM?
    Well, noise is speed dependent, so the more congested traffic the less overall noise, and I don't know how you'd link capacity to QOL as an indicator...can't you keep a current metric like walk score or something? What are you trying to show with capacity?
    -------
    Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.

  3. #3
    Quote Originally posted by ColoGI View post
    Well, noise is speed dependent, so the more congested traffic the less overall noise, and I don't know how you'd link capacity to QOL as an indicator...can't you keep a current metric like walk score or something? What are you trying to show with capacity?
    Consultants are trying to portray QOL unaffected by increased traffic (reassigned as part of a major project) in the urban grid. I tend not to agree but I can't seem to place my disagreement on something tangible.

  4. #4
    Cyburbian Tarf's avatar
    Registered
    Jul 2011
    Location
    Encinitas, CA
    Posts
    705
    Quote Originally posted by Gedunker View post
    Consultants are trying to portray QOL unaffected by increased traffic (reassigned as part of a major project) in the urban grid. I tend not to agree but I can't seem to place my disagreement on something tangible.
    I grew up in suburbia. Very low traffic. Also: no schools, no retail, trails to nowhere. While a safe place to grow up, it sucked. I would judge it to have a very low quality of life.

    By contrast, one of the best places I ever lived was downtown Spokane. Much higher traffic volumes, but also was within walking distance of everything. I loved it.

    I don't think you can merely link vehicle volumes to quality of life - at least, not without considering some other things like density, speed of traffic, etc. etc.
    In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move. (Douglas Adams)

  5. #5
    Cyburbian Random Traffic Guy's avatar
    Registered
    Jul 2005
    Location
    Lone Star State
    Posts
    630
    Some kind of metric can be made, but it would be arbitrary (like LOS thresholds for delay in traffic engineering) and would likely vary somewhat by the area (which is no problem). Could definitely be useful if bought into by the community, everyone just has to realize that the results will be much lower than traditional vehicle capacity would indicate (see below). The new 2010 HCM has started somewhat down this path with the multimodal LOS that at least considers non-auto movement, but not the same thing.

    I have often thought of this since we are asked to do link analyses on lots of streets around here. And in residential areas, the theoretical capacity of a residential street is much higher than what the adjacent residents would consider possible, so the whole thing is just silly. For example, by local standards a residential lane has capacity of 525 vehicles per hour in a suburban area. That's just pure capacity, how many cars can fit down the lane considering it has a suburban speed and level of friction on the edges. Capacity declines as you go towards CBD, there's 5 area categories. So for a 2-lane "major neighborhood" street that is the main access to a development, kind of a collector but with houses fronting it, which is wide enough for 2 lanes to always travel even with parked cars on both sides, would have a capacity of 1,050 vehicles per hour. Daily capacity is considered 10 times the hourly (so 10,500 daily), which is already a type of quality of life limit since theoretically it should be 24 times if you're just looking at how many vehicles can get past a point. But your street with 1,050 hourly and 10,500 daily capacity likely handles say 200 in the busiest hour and perhaps 2,000 in the whole day, and this is considered the busiest, fastest, most dangerous street in the neighborhood. But by looking at capacity alone you can add 250/2,500 and still be within LOS A/B, who could argue with that? LOS C up to 0.65 V/C or 680 in an hour and 6,825 daily. "Still acceptable" LOS D up to 0.80 V/C or 840 in an hour and 8,400 daily... Just ridiculous in a suburban setting.


    Thus the #1 item on my family's house hunting checklist is "not on a street with a center stripe".

  6. #6
    Cyburbian DetroitPlanner's avatar
    Registered
    Mar 2004
    Location
    Where the weak are killed and eaten.
    Posts
    6,185
    Large capacity vehicles are generally seen as bad when it comes to SUVs.

    Low capacity vehicles such as Smart Cars are seen as toys.

    Things can be said for using large capacity vehicles when capacity nears full utilization.

    Near empty buses are seen as the enemy to most suburban dwelllers around here. Proof that they are getting screwed. Typically the same folks who complain about empty buses are far away from the areas where the buses are fully utilized. They seem to have a disconnect that they live at the end of the line.

    Noise is becoming less of an issue. People are starting to conflict with cars like the Prius and Volt because they don't hear them coming. I don't know what you can do about heavier vehicles such as large trucks, that cause most of the vibration issues.

    My take: Double edged sword, you can't win.

    The best you can do is try to have an education campaign directed to the folks who may be empty nesters, but can not see driving anything but a Chevy Tahoe. Trying to force them into buying something they don't want will get you labeled a commie or anti-family.
    We hope for better things; it will arise from the ashes - Fr Gabriel Richard 1805

  7. #7
    Quote Originally posted by Tarf View post
    <snip>

    By contrast, one of the best places I ever lived was downtown Spokane. Much higher traffic volumes, but also was within walking distance of everything. I loved it.
    On a smaller scale, that's the environment I'm talking about. The typical homeowner or tenant lives there for all of the reasons they enjoy, despite the higher than anywhere else in town traffic.

    Quote Originally posted by Tarf View post
    I don't think you can merely link vehicle volumes to quality of life - at least, not without considering some other things like density, speed of traffic, etc. etc.
    The question, though, is when does that one vehicle tip the scale from "Lovin' it" to "Hating it"? The scale's there, I just can't believe something like VCA can tell you where the fulcrum point rests.

  8. #8
    Cyburbian Tarf's avatar
    Registered
    Jul 2011
    Location
    Encinitas, CA
    Posts
    705
    Quote Originally posted by Gedunker View post
    The question, though, is when does that one vehicle tip the scale from "Lovin' it" to "Hating it"? The scale's there, I just can't believe something like VCA can tell you where the fulcrum point rests.

    It's all about context.

    If you live in an area with 30 +/- dwelling units per acre, higher volumes can be acceptable without degrading quality of life. If you live in an area of 3 dwelling units per acre, there is a much greater sensitivity to traffic volumes. As to where that scale tips... it's going to be a spectrum, and will vary from person to person.
    In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move. (Douglas Adams)

  9. #9
    Cyburbian transguy's avatar
    Registered
    Jan 2006
    Location
    Midwest-ish
    Posts
    218
    Nothing directly on topic to add to what has been said, but you could also use this opportunity to education your elected officials on how decisions if the past to require excessive pavement width can now impact adjacent residential uses along the roadway. Not sure if this is an issue or not for you, but I think I would love this to come up for me so I could say "I told you so!"
    Much work remains to be done before we can announce our total failure to make any progress.

  10. #10
    Cyburbian ColoGI's avatar
    Registered
    Jul 2009
    Location
    Colo Front Range
    Posts
    2,395
    Quote Originally posted by Gedunker View post
    Consultants are trying to portray QOL unaffected by increased traffic (reassigned as part of a major project) in the urban grid. I tend not to agree but I can't seem to place my disagreement on something tangible.
    Depending on the context of your street networks, likely you'll have increased emissions and a good chance of increased bike accidents. Whether there is an increase in disamenity to other non-motorized users is impossible to tell from here. Nonetheless, if a community values its small-town feel and you're increasing pop. and traffic, you are going to get conflict. Just such a story in my RSS feed today about the boom in NoDak.

    But I get the question now: road capacity for TPD/VMT and not individual vehicle capacity for occupancy is the metric. ;o) Sure you can use that, but as above it is subjective. Not sure how it stands on its own...
    -------
    Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.

  11. #11
    Cyburbian wahday's avatar
    Registered
    May 2005
    Location
    New Town
    Posts
    3,826
    I agree with the double-edged sword nature in linking this kind of measurement to QOL. Higher traffic volumes are also what makes it possible to have certain types of stores and other amenities that increase QOL in other ways (including walkability). With lower traffic volumes, many retailers either won't locate in the area or will try and possibly fail. Which is not to say that higher volume is always going to attract such amenities, either.

    One also might want to consider the nature of the traffic in question. I live near a major arterial that is 4 lanes with a large median. But the traffic volume it handles occurs primarily during rush hour. At night and in the middle of the day, the street has very light traffic that could easily be handled by a 2 lane road. So, we have this big boulevard that is difficult to cross during peak drive times but also when its slow because its so damn wide, negatively impacting the walkability of the area. Indeed, we have seen a lot of turnover in reatil in this strip in recent years.

    I don't think its a bad idea, I just think you may want to nuance the metric a little and include/incorporate some additional factors if you want to link traffic volume it to QOL.
    The purpose of life is a life of purpose

  12. #12
    Cyburbian Iron Ring's avatar
    Registered
    Nov 2005
    Location
    In the "Interior".
    Posts
    90
    Obviously QOL can be very subjective, but if you're aiming for a fairly simple "indicator" of QOL I would avoid measures of traffic capacity (i.e. delay, HCM level of service, volume/capacity ratios). These can often be very counter to QOL. As many have mentioned, a street with say LOS = B could just as easily be a 6 lane arterial with high speed traffic as a low volume residential street.

    I might aim toward a combination of observed traffic volume and speed. When it comes down to it many of the traffic related impacts (safety for bikes and peds, noise, ability to cross, comfort, etc...) are related to either volume or speed. If you have the data, you could look at the volumes and speeds of different streets in your community to relate it back to the specific case.

  13. #13
    Cyburbian Seabishop's avatar
    Registered
    Nov 2002
    Location
    USA
    Posts
    3,664
    I think its a stretch to relate the two in a direct way. There's a saying that "Level of Service F = Fun" because the parts of town with the most traffic congestion are often the places people want to spend time or live in. Equating traffic congestion with a lower quality of life seems pretty biased against urban living in my opinion.

+ Reply to thread

More at Cyburbia

  1. Replies: 15
    Last post: 27 Aug 2007, 8:11 PM
  2. Replies: 15
    Last post: 24 Feb 2006, 4:47 PM
  3. Replies: 42
    Last post: 20 Jan 2004, 8:09 AM
  4. Replies: 4
    Last post: 17 Nov 2003, 8:41 AM
  5. Community Quality of Life Surveys
    Economic and Community Development
    Replies: 9
    Last post: 03 Apr 2002, 3:14 PM