Cities Turning to Bicycles



Frank Krygowski wrote:

> Daniel J. Stern wrote:
>
>> On Tue, 5 Oct 2004, Frank Krygowski wrote:
>>
>>
>>> http://www.thecarconnection.com/index.asp?n=163,172&sid=172&article=3252:
>>>
>>>
>>> "The usual range of properly aimed headlights is about 150 feet for low
>>> beams and 350 to 400 feet for high beams."

>>
>>
>>
>> Horseshit. And yes, I'm quite qualified to judge that and say it.

>
>
> :) Oh, and I'm sure your qualifications are just excellent! Why, we
> have your opinion on them - and what more would we need? ;-)
>


Oh, this is good.

nate


--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Frank Krygowski wrote:

> Matthew Russotto wrote:
>
>> In article <[email protected]>,
>> Frank Krygowski <[email protected]> wrote:
>>
>>> My issue is roads that get shared by pedestrians, bicyclists, farm
>>> tractors, horse-drawn vehicles, cautious elderly drivers and the like.

>>
>>
>>
>> Then why are you insisting on "solutions" (speed bumps) which are bad
>> for cars,
>> bicyclists, tractors, horse-drawn vehicles, and cautious elderly
>> drivers?

>
>
> <sigh> Yet another person who can't retain the difference between speed
> BUMPS and speed HUMPS.
>
> I've pointed to the definitions perhaps a dozen times. Please do some
> reading on your own. If you don't know the vocabulary, you can't
> discuss the topic intelligently.
>


To non-automobile traffic, there really isn't much difference, they are
still unpleasant and annoying. To an automobile owner, the difference
is that bumps and improperly-designed humps can be dangerous, while your
ideal (never seen in the wild) humps are, again, merely annoying (but
ineffectual.)

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Frank Krygowski wrote:

> Arif Khokar wrote:
>
>> Nate Nagel wrote:
>>
>>> but there are similar signs on every exit ramp on many highways, most
>>> of which are safely navigable at much higher speeds.

>>
>>
>>
>> I believe that some of the advisory signs correspond to the speed
>> limit of the road that one is exiting onto. At least that's what I've
>> seen with advisory signs for speeds that are way too low for the given
>> curvature of an exit ramp. Traffic engineers should seriously
>> consider using the "Reduced Speed Ahead" / "Speed Limit xx MPH"
>> combination instead of a meaningless advisory sign.

>
>
> As with Brent, if that's your serious proposal, you should start working
> on it. At least, write letters to the editor, or to your state DOT.


I agree.

>
> If you're sufficiently convincing, you'll see a change. Traffic
> engineers get lots of advice from the public, because nearly all
> motorists are pretty expert in road design, legal issues, state budget
> priorities, etc.
>


Oh, I'm sorry, I thought you were actually starting an intelligent post.
Now realize you were just being a *****, as usual.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Frank Krygowski wrote:

> Nate Nagel wrote:
>
>> Frank Krygowski wrote:
>>
>>> Nate Nagel wrote:
>>>
>>>>
>>>>
>>>> are you *sure* you drove this stretch of road?
>>>
>>>
>>> There's no other way to go by freeway from the Carolinas, through WV,
>>> west of Pittsburgh and to the PA turnpike.

>>
>>
>> Actually, you could have taken I-81 to US-15 to I-76, although that
>> passes *east* of Pittsburgh (closer to Harrisburg.)

>
>
> Oh good grief.
>
> Heading north from North Carolina. Into Virginia. Into West Virginia.
> Through Beckley, is it? And I think it's Route 19, the
> finally-completed highway? Over the New River Gorge? Pick up the
> interstate through the Morgantown area? And yes, WEST of Pittsburgh to
> the Turnpike. All interstate except for WV 19, or whatever that number is.
>
> Nate, you're making yourself look silly.
>


No, actually, *you* are, as if you had driven the road as you claim you
have, you would remember that feature. I dare say that that is one of
the few roadways that one can legitimately claim that *nobody* who has
driven through it ever forgets.

yes, your description is correct, but anyone with a computer could have
looked that up on a map in minutes.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Frank Krygowski wrote:

> Brent P wrote:
>
>> In article <[email protected]>, Frank Krygowski wrote:
>>
>>
>>> You (and Brent) perceive a problem on the distant freeways. And you
>>> think _nothing_ should be done to alleviate their problems until
>>> _your_ problem is solved to _your_ liking.

>>
>>
>>
>> You treat symptoms frank. You strike me similiar to some engineers I
>> have worked with running from one problem to the next never looking at
>> the system as whole. Never seeing the cause and effect relationships
>> between
>> things. You go from fighting one fire to next never understanding how
>> to lessen the work load and really solve the problems once and for all.
>>
>>
>>> It's hard to believe anyone would take your argument seriously.

>>
>>
>>
>> Frank, mostly what you've done is insult anyone who disagrees with you
>> and talk down to them. That's what passes for your primary 'arguement'.
>> I take the road system and road safety as an engineering problem and I
>> set out to find root causes and find real, lasting changes for the
>> better just as I do on the job. You take the route of patching and
>> firefighting. I want thoughtful design, you want kludges.

>
>
>
> To continue your analogy:
>
> Brent the firefighter: "I keep telling you, the solution is to build
> all our buildings from fireproor materials! Anything else is a kludge!"
>
> Homeowners: "BUT OUR HOUSES ARE BURNING! OUR KIDS ARE IN THERE!"
>
> Brent: "Yes, yes, ma'am, I know about your child, but hear my out! This
> is a beautiful plan..."
>


No, the situation is more like, there is a grease fire in a kitchen.
Brent is proposing to put it out with a fire extinguisher and then
investigate why it occurred. Your solution is to call the fire
department and break down the door with axes and hose the kitchen down
with high pressure water. Your way *may* put out the fire, but is
infinitely more destructive and doesn't do anything towards preventing
the problem from recurring, either in the same place or elsewhere, in
the future.

nate


--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
In article <[email protected]>, Nate Nagel wrote:
> Frank Krygowski wrote:
>
>> Daniel J. Stern wrote:
>>
>>> On Tue, 5 Oct 2004, Frank Krygowski wrote:
>>>
>>>
>>>> http://www.thecarconnection.com/index.asp?n=163,172&sid=172&article=3252:
>>>>
>>>>
>>>> "The usual range of properly aimed headlights is about 150 feet for low
>>>> beams and 350 to 400 feet for high beams."
>>>
>>>
>>>
>>> Horseshit. And yes, I'm quite qualified to judge that and say it.

>>
>>
>> :) Oh, and I'm sure your qualifications are just excellent! Why, we
>> have your opinion on them - and what more would we need? ;-)
>>

>
> Oh, this is good.


this will be amusing.
 
In article <[email protected]>, Frank Krygowski wrote:
> Brent P wrote:
>
>> In article <[email protected]>, Frank Krygowski wrote:
>>
>>>So don't ask others to put up with the effects of your failed mission.

>>
>>
>> My failed mission? What's failed is the last 60 years of doing things
>> your way.

>
> My way is installing speed humps in residential neighborhoods. The
> concept is relatively new, certainly not 60 years old. And it's
> apparently quite successful.


The overall theme of treating symptoms and using patches which has
resulted in this latest patching concept.

And digging a big trench in the road would also be successful. No one
claimed they aren't successful in lowering traffic speeds, it's the
downsides of that success that people object to.
 
Frank Krygowski wrote:

> Nate Nagel wrote:
>
>> Frank Krygowski wrote:
>>
>>> I think you simply need to drive slower. Or perhaps pay more
>>> attention to the road ahead. This isn't rocket science.
>>>

>>
>> Explain to me again how "paying attention" will help one detect a
>> decreasing radius curve that isn't possible to see from the approach.

>
>
> ??? What can I say? You watch the contours of the road ahead.


the ones you can't see. Right.

> You
> don't drive on the _assumption_ that the road will curve the way you
> like. You pay attention!
>


You're just being deliberately obtuse. It's standard design practice
for any curve on an Interstate to only *increase* in radius, not
decrease. You can see about 70-80 degrees into the curve as you
approach. The radius decreases *sharply* after that point - but it's
hidden by the supports for the I-70 overpass. There is no logical
reason for it to be that way, but it is.

The whole point is not what *I* did in that situation, the point is that
it's hazardous because the danger of driving too fast IS NOT EVIDENT
until it's too late. Therefore, advisory signs are posted; but they are
ineffective (as evidenced by the marks on the barriers.) They are
ineffective because the motoring public, as a whole, has been
conditioned to completely ignore any advisory signs as 98% of the time
they are completely meaningless in terms of selecting a safe speed for
travel. And, of course, that brings us back to the point that I made so
long ago - people don't respect the speed limit in your neighborhood
because they've been conditioned to not respect the speed limit, period.


> Why is this so hard for you, when so many people don't have your
> problems? Aren't you ashamed of your relative incompetence??


Only thing I'm ashamed of is being baited into this long, stupid
exchange. However, it beats laundry. I think.

>
> And what _do_ you do when you're driving on two-lane mountain roads??
>


Ummm... drive?

nate
--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
In article <[email protected]>, Tim McNamara wrote:

> Indeed, my review of some of the traffic management literature (e.g.,
> http://ops.fhwa.dot.gov/Travel/traffic/freeway_management_handbook/chapter5.htm)
> suggests that traffic flow obeys the mathematics governing hydraulic
> flow, and that there is a maximum throughput in any hydraulic system
> before turbulence is created. Turbulence in turn creates drag and
> slows throughput dramatically. You can set the speed limit at the
> 85th percentile, but that will not "smooth out" traffic flow when
> there are just too many cars on the road at the same time- which is
> about 8 hours of every day in major urban areas.


A smooth flow can sustain a higher throughput delaying the onset of
traffic jams and lessening how long they last.
 
Frank Krygowski wrote:

> Nate Nagel wrote:
>
>> Frank Krygowski wrote:
>>
>>> Nate Nagel wrote:
>>>
>>>> Frank Krygowski wrote:
>>>>
>>>>> If a person were to apply _real_ reading comprehension to your
>>>>> paragraph, they'd note that you never actually said what that car's
>>>>> headlights were, other than "not stock." Now are you seriously
>>>>> claiming that they gave you adequate visibility on a rural two-lane
>>>>> road at 75+ mph? Unless you'd hung driving lights all over the
>>>>> front end, I find that highly doubtful.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> No, just everyday high-output halogens from the parts store, with a
>>>> properly maintained electrical system. It's not rocket science.
>>>
>>>
>>>
>>>
>>> http://www.ou.edu/oupd/nightdr.htm

>>
>>
>>
>> Just took a closer look at that site. There are some more glaring
>> (heh) errors in the assumptions they've made.
>>
>> 1) the distances calculated for "reaction time" are based on a
>> reaction time of 1.5 seconds. If it takes you 1.5 seconds to
>> recognize a hazard and react to it, it's probably time for a motorized
>> wheelchair.
>>
>> 2) There's no mention at all of what headlights were used to calculate
>> the visible distance numbers, and as I and other posters have pointed
>> out, they were all based on some generic "low beam" headlight.
>> Obviously when one's driving at night on a mostly deserted road, one
>> is using high beams unless there's oncoming traffic or you are
>> approaching or being passed by traffic in the same direction.
>>
>> 3) The site also assumes a coefficient of friction of 1.0 which is
>> fairly optimistic, about the only way that's achieved with normal
>> tires is on dry, clean asphalt. Granted, asphalt is becoming more and
>> more prevalent, but there are still a few concrete-paved highways left.
>>
>> 4) "deceleration" is listed as 17.02 ft/s^2. What the heck? If the
>> coefficient of friction is 1.0, the deceleration of the vehicle should
>> be appx. 32 ft/s^2. sounds like a "rectal number" to me, and what's
>> worse, it's given four significant digits, implying a precision that
>> isn't there - deceleration can and indeed does vary even over the
>> course of one braking maneuver due to weight transfer and the fact
>> that a typical tire/road interface does not have a constant mu when
>> load varies greatly (and, of course, it changes with the degree of
>> slip of the tire vs. the road as well, but I'm assuming that we're
>> talking about a panic stop sith a skilled driver here, so only 5-10%
>> slip not 100% as in a locked wheel stop.)
>>
>> nate
>>

>
> If you want to delve deeply into the psychology and physics, we can do
> it. But self-proclaimed "skilled drivers" are seldom as fast in
> reaction as they pretend. Unanticipated events take quite a while to
> process.
>
> The coefficient of friction = 1 is high no doubt; , and as is obvious
> from elementary physics, they're not basing the deceleration on that
> value.


so what are they basing it on then? Certainly not real world stopping
distances - they are way long. Check the back of any car mag for their
summary of the last couple years' road tests.

> But to get back to reality: Imagine your bias-ply tires after
> the first 100 feet of a panic stop from 75+ mph. The rubber temperature
> would be WAY up - in fact, you'd have left large amounts on the road -
> so the coefficient of friction has dropped tremendously.


a) I (why am I saying "I"? I wasn't driving, but you're completely
ignoring that fact) wouldn't have left "large amounts of rubber on the
road" - the best decel is usually found at maybe 5-10% slip, to leave
"large amounts of rubber" I would have to have locked the brakes up
completely.

b) You obviously know exactly squat about tires, as even if I did manage
to get the rubber temperature "WAY up" - that would be a GOOD THING.
The coefficient of friction does not "drop tremendously" with increased
temperature, it actually goes UP. If I'm wrong, you better tell all
those drag racers that they're just wasting fuel and tire rubber doing
all those long, smoky burnouts - they ought to be able to accelerate
faster if they just stage and go. The only detrimental effects of heat
in tires are shorter tread life, increased risk of a blowout if too-high
temperatures are maintained for a long period of time, and the risk of
"blistering" the tread. Reduced traction is generally not a problem.


> You don't know
> the road surface


No, *you* don't. I was there.

> - you may be trying to brake on a surface lubricated by
> road apples, further reducing "mu". Your car's weight is biased far
> forward, the rear is jacking up, and (correct me if I'm wrong) that
> Studebaker had no brake proportioning valve, so your rear brakes are
> likely locking.


You mean a major automotive mfgr. deliberately released a defective
product? Well, that's happened a few times before, but not in this
case. You're actually partly right - there's no prop valve, but they
did compensate for the increased line pressure required to activate the
front discs by fitting non-self-energizing drums in the rear as opposed
to the normal self-energizing type, and then making a power booster
standard equipment to reduce pedal effort, which would otherwise have
been high. As usual, if you overdo it with the brake pedal, the fronts
will still lock first.

> That means you're losing attitude control, and the rear
> has begun swinging around. The road has a camber (as do essentially all
> two-lanes) so you're drifting right.


Only if you've locked up any wheels.

> The only way to regain control is
> to reduce the deceleration rate, either by easing off the pedal or by
> rapidly pumping the brake. You're now trying to find that precise
> boundary between kinetic and static friction - which you haven't
> practiced in this car,


I wasn't driving. The driver has been driving Studes since they were
still in production.

> and which wouldn't help if you had, because the
> tire tread is now nearly molten,


again, were that possible, that would be a Good Thing

> and the hot rear drum brakes are
> behaving erratically.


That's the first almost-factual thing you've said in this post. The
real limiting factor in a panic stop, other than the tires, is the
temperature of the brake components. However, hot brakes don't "behave
erratically" - once they get above their optimum temperature, they just
don't work as well, commonly known as "brake fade." However,
contemporary road tests of similar vehicles are full of phrases like "no
perceptible brake fade in repeated stops from 80 MPH" etc. etc. etc. and
my own experiences driving these cars bear that out (not that I drive in
such a manner as to have required repeated hard stops from any
significant speed; but neither have I noticed any shortcomings with any
Stude braking system, disc or drum.)

> And to make matters worse, you've just peed your
> pants. If you do stop in time, you've got a mess to clean up.
>


Right.

> And that's how messy real life is, compared to the fantasies of boy
> drivers.
>


Again, you mean the 65 year old guy that was driving? The guy who owned
the car, and had a significant financial investment in it?

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Frank Krygowski wrote:

> Nate Nagel wrote:
>
>> Frank Krygowski wrote:
>>
>>>
>>> http://www.ou.edu/oupd/nightdr.htm

>>
>>
>>
>> Fortunately, this car was also equipped with a little button on the
>> floor, next to the clutch pedal, which activated a cirucuit which lit
>> a secondary set of filaments in the headlights which allowed one to
>> see much farther down the road. I believe they are known colloquially
>> as "high beams."

>
>
>
> From
> http://www.thecarconnection.com/index.asp?n=163,172&sid=172&article=3252:
>
> "The usual range of properly aimed headlights is about 150 feet for low
> beams and 350 to 400 feet for high beams."
>


A ******** number.

>
> And again, from http://www.ou.edu/oupd/nightdr.htm, stopping distance at
> 70 mph is roughly 460 feet. But our heroes were doing "75+ mph." That
> same site gives a stopping distance of 580 feet for 80 mph.


Another ******** number.

>
> Say 530 feet at "75+". With 400 foot headlights. Don't you guys
> recognize when you should be embarrassed?
>


Get some real values and then tell us who should be embarrassed.

>
>
> I'm sure that in your mind, the Studebaker was _much_ better at panic
> stops than a typical car, right? ;-)


In my mind, as well as the minds of most automotive writers of the era.

> And I'm sure that you precisely
> tweaked the headlight voltage and aiming to get a few more feet out of
> those headlight beams, right? ;-)


The car was running at about 14.7V and the headlights were correctly
aimed. Why you appear to assume otherwise is beyond me.

> And of course, we _know_ that, like
> almost all Americans, you're better than average drivers, right? ;-)
>


That's not really that difficult, but yes.


> But despite all the "Boy, am I good" self-delusion that you treasure,
> it's _still_ true that rural two-lane roads feature curves, hills,
> interesections and blind spots.


There were no curves, hills, intersections, or blind spots.

> They can have all sorts of obstructions
> or potential victims in the road. And the driving you describe, defend
> and brag about was illegal, irresponsible and stupid.


No, it's a perfectly appropriate speed for the road, and the few other
drivers that we encountered seemed to agree.

>
> What's amazing is that you do this in a thread where you're arguing that
> your judgement is better than that of highway officials and neighborhood
> residents.


The fact that my judgement is better than that of the people that put up
highway signs is not exactly news. The fact that my judgement is better
than some busybody who advocates throwing up lumps of asphalt in the
middle of the road is not particularly impressive.


> You argue that you should be able to choose your own speed
> through neighborhoods, and as evidence, you brag about your
> irresponsible driving.


No, I related an anecdote of normal, safe driving in a 40-year old car
being illegal - as an example of how our laws are out of touch with reality.

>
> Not only are you losing the argument on a factual basis, you're shooting
> yourself in the foot with your own bragging.
>


Who is bragging?

>
>
>>> Well, what I read was that they were an option. I'm no expert on
>>> Studebakers, so maybe you can show me a site that proves what you say.
>>>

>>
>> WTF? You're really a piece of work, you know that, right? I can do
>> better than provice a "site," give me a few days and I'll scan an
>> original print ad for the car. Been meaning to anyway, as I don't
>> believe that it's on the Web anywhere yet.

>
>
> That's fine.


I'm glad that it meets with your approval. It means so much to me.

> As I said, it's a minor point.


If it's a minor point, why are you making such a big deal out of it?

> If that 1963 car had front
> disks, that would bring its stopping distance down a bit - i.e. it
> wouldn't take 700 feet to stop from your 75+ mph; perhaps only 630 feet.


I actually can't provide a number for braking distance for the car, as
contemporary road tests generally only provided data for acceleration
and top speed; braking tests were generally subjective. However, "630
feet" is ludicrous. Think about that number - that's two football
fields and then some. If I honestly felt that the car couldn't stop
shorter than that, I would have refused to get in it.

> Your driver buddy would be overdriving the headlights by a little bit
> less.
>


Right.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
"Alan Baker" <[email protected]> wrote in message
news:[email protected]...
> Do you really think that we (as a society) should spend money misleading
> people as to what speed is appropriate for access ramps?


How do you propose that they set a speed that will work for everyone?

Should they set it real low to make sure the guy in the 4x4 with the
6 inch lift kit won't have a problem? What exactly should they use
as proper criteria for setting the recommended speed?
 
Matthew Russotto wrote:

> In article <[email protected]>,
> Frank Krygowski <[email protected]> wrote:
>
>>Matthew Russotto wrote:
>>
>>>
>>>Then why are you insisting on "solutions" (speed bumps) which are bad for cars,
>>>bicyclists, tractors, horse-drawn vehicles, and cautious elderly
>>>drivers?

>>
>><sigh> Yet another person who can't retain the difference between speed
>>BUMPS and speed HUMPS.

>
>
> Sorry, you've already said that "As I see it, even a sharp speed bump
> in a residential roadway will do what I want - lower speeds in residential
> neighborhoods. ... So it sounds like my job is to advocate _some_ type
> of speed hump or bump." The distinction you make elsewhere is a
> disarming tactic, bait and switch. You point people to speed "humps"
> when they object to your nonsense and then you advocate for any sort
> of surface hazard you can.


But I'm not "insisting on "solutions" (speed bumps)," as you claimed
above. I'll certainly accept speed humps.

Sheesh. Reading comprehension, reading comprehension!

Furthermore, even the longer and lower
> obstructions you mention are bad for bicyclists, horse-drawn vehicles,
> and cautious elderly drivers.


Not in my experience, and not from what I've heard.

It may be (I don't know) that if a cyclist or horse-cart goes more than
25 mph over one of these features, there may be trouble - but then, they
shouldn't break the speed limit either, I suppose.

In any case, I've biked over them with no problem. One of my bicycling
buddies has them on his residential street, in fact. They're kind of
fun, actually.

>
>>I've pointed to the definitions perhaps a dozen times. Please do some
>>reading on your own. If you don't know the vocabulary, you can't
>>discuss the topic intelligently.

>
>
> Why would I adopt my opponent's vocabulary?


Because it's correct.

--
Frank Krygowski [To reply, remove rodent and vegetable dot com.
Substitute cc dot ysu dot
edu]
 
"Alan Baker" <[email protected]> wrote in message
news:[email protected]...
> Oh, please. The simple fact -- and you know it as well as I -- is that
> access ramp advisory speeds are *ludicrously* low almost *all* the time.
>
> They should reflect an appropriate speed for an average vehicle, in good
> weather, being properly driven. Instead, they are most frequently less
> than half that speed.


I have never once seen a speed that was set at less than half the
speed that a reasonable vehicle could handle.
 
"Frank Krygowski" <[email protected]> wrote in message
news:[email protected]...
> I'm not interested in excuses about how difficult decreasing radii can be


This is bad design. For a PE to say what you just said is ridiculous.
To resort to a decreasing radius means that the overall design is flawed.

You should be able to go through a curve without needing to slow
down the whole time. This is how you end up with trucks on their
side with their cargo spilled all over the place.
 
Tim McNamara wrote:

> Frank Krygowski <[email protected]> writes:
>
>
>>Brent P wrote:
>>
>>
>>>In article <[email protected]>, Frank Krygowski wrote:
>>>
>>>
>>>>If you want to delve deeply into the psychology and physics, we
>>>>can do it. But self-proclaimed "skilled drivers" are seldom as
>>>>fast in reaction as they pretend. Unanticipated events take quite
>>>>a while to process.

>>
>>>If the speed kills stuff you proclaim is correct, chicago area
>>>expressways would be coated in blood 24 hours a day, 7 days a week.
>>>The dan ryan expressway alone shows reaction times are far better
>>>than what you are saying. But that's neither here nor
>>>there. smoothing out the flow greatly reduces the number of events
>>>to react to. 85th percentile speed limits are key to smoothing the
>>>traffic flow.

>
>
> Would that it were that simple, but it isn't. Competent road design-
> something that is distinctly lacking on most roads- is one of the
> keys. Development of higher standards for obtaining a license to
> drive would be another. The absolute speed of driving isn't as much
> issue as the bottlenecks caused by road design problems and the
> interaction between vehicles.
>
> Indeed, my review of some of the traffic management literature (e.g.,
> http://ops.fhwa.dot.gov/Travel/traffic/freeway_management_handbook/chapter5.htm)
> suggests that traffic flow obeys the mathematics governing hydraulic
> flow, and that there is a maximum throughput in any hydraulic system
> before turbulence is created. Turbulence in turn creates drag and
> slows throughput dramatically. You can set the speed limit at the
> 85th percentile, but that will not "smooth out" traffic flow when
> there are just too many cars on the road at the same time- which is
> about 8 hours of every day in major urban areas.


It will smooth out the flow a little by narrowing the distribution of
speeds, but you're right, that's a minor effect. It will, however,
increase the capacity of the road by allowing people to spend less time
on it (ASSuming, of course, that it's grossly underposted to the point
where speeds are artificially depressed now.)

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Mark Jones wrote:

> "Alan Baker" <[email protected]> wrote in message
> news:[email protected]...
>
>>Do you really think that we (as a society) should spend money misleading
>>people as to what speed is appropriate for access ramps?

>
>
> How do you propose that they set a speed that will work for everyone?
>
> Should they set it real low to make sure the guy in the 4x4 with the
> 6 inch lift kit won't have a problem? What exactly should they use
> as proper criteria for setting the recommended speed?
>


Since the limiting factor is usually cornering, I would set the advisory
speed such that a maximum G-force would not be exceeded taking the
center of the roadway through the entire feature. Say maybe 0.25G -
0.3G is generally where most drivers start to feel uncomfortable, but it
is actually well below the capabilities of most cars in ideal
conditions. The point is not to try to make the speed 100% applicable
to all cars - it is an advisory sign, after all, not a speed limit. It
should, however, be consistent everywhere so drivers can have confidence
in what they are being told. e.g. a driver in a Porsche might drive
through an offramp a little faster than the advisory sign suggested, but
a semi truck may drive a little slower, but both have gained useful
knowledge from the sign.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel
 
Nate Nagel wrote:

> Frank Krygowski wrote:
>
>>>> http://www.ou.edu/oupd/nightdr.htm
>>>

>>
>> From
>> http://www.thecarconnection.com/index.asp?n=163,172&sid=172&article=3252:
>>
>> "The usual range of properly aimed headlights is about 150 feet for
>> low beams and 350 to 400 feet for high beams."
>>

>
> Get some real values and then tell us who should be embarrassed.


So far, I'm the only one who's produced values. Do you have some? Put
them up and we can discuss. If not, you really shouldn't complain about
mine.

>>
>> I'm sure that in your mind, the Studebaker was _much_ better at panic
>> stops than a typical car, right? ;-)

>
>
> In my mind, as well as the minds of most automotive writers of the era.


When I said "The typical car," I meant of _this_ era. The websites I
listed were contemporary - not 1963 vintage!

The rest of your post amounts to exactly what I predicted: that boy,
that old Studebaker had terrific brakes! And its headlights were perfect
or better! And this rural two lane road was guaranteed to be straight,
well-paved and deserted. And that if anything _did_ happen, of _course_
it would have been taken care of with perfect aplomb. And as a last
tidbit, naturally, you're a better than average driver - just like 85%
of the American drivers surveyed.

And as evidence of all that, we have ... well, actually, all we have are
your admission of nearly losing it on a freeway, and your personal need
for super-accurate speed advisory signs.

IOW, You're making no sense. And you're demonstrating in every way
possible that you can't be trusted to drive responsibly, to choose your
own reasonable speed. You make a _strong_ case for strict speed limit
enforcement.



--
Frank Krygowski [To reply, remove rodent and vegetable dot com.
Substitute cc dot ysu dot
edu]
 
Nate Nagel wrote:

> Frank Krygowski wrote:
>
>> Arif Khokar wrote:
>>
>>> Nate Nagel wrote:
>>>
>>>> but there are similar signs on every exit ramp on many highways,
>>>> most of which are safely navigable at much higher speeds.
>>>
>>>
>>>
>>>
>>> I believe that some of the advisory signs correspond to the speed
>>> limit of the road that one is exiting onto. At least that's what
>>> I've seen with advisory signs for speeds that are way too low for the
>>> given curvature of an exit ramp. Traffic engineers should seriously
>>> consider using the "Reduced Speed Ahead" / "Speed Limit xx MPH"
>>> combination instead of a meaningless advisory sign.

>>
>>
>>
>> As with Brent, if that's your serious proposal, you should start
>> working on it. At least, write letters to the editor, or to your
>> state DOT.

>
>
> I agree.
>
>>
>> If you're sufficiently convincing, you'll see a change. Traffic
>> engineers get lots of advice from the public, because nearly all
>> motorists are pretty expert in road design, legal issues, state budget
>> priorities, etc.
>>

>
> Oh, I'm sorry, I thought you were actually starting an intelligent post.
> Now realize you were just being a *****, as usual.



Ever notice how some people's language deteriorates when they've made a
fool of themselves in a discussion? ;-)

If you guys do write those letters, you'll be more convincing if you
keep the obscenities under control.


--
Frank Krygowski [To reply, remove rodent and vegetable dot com.
Substitute cc dot ysu dot
edu]
 
Nate Nagel wrote:

>
>
> yes, your description is correct, but anyone with a computer could have
> looked that up on a map in minutes.


I can't prove this, of course, but: Sorry, I did not look that up on a
computer. Nor a road map. I looked on the US map on my wall (no roads
shown) to remember the name of Beckley.


--
Frank Krygowski [To reply, remove rodent and vegetable dot com.
Substitute cc dot ysu dot
edu]
 

Similar threads