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About this blog: Real power doesn't reside with those who make the final decision, but with those who decide what qualifies as the viable choices. I stumbled across this insight as a teenager (in the 1960s). As a grad student, I belonged to an org...  (More)

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Bad question, useless answers: Traffic policy GIGO

Uploaded: Sep 17, 2015
City Hall is currently requesting citizen input on fundamental policy related to traffic and transportation issues. The currently advertised question (via Nextdoor) is "Do you find that traffic calming is an effective way to slow traffic in your neighborhood?" The term "traffic calming" has been bastardized far beyond the point where calling it a euphemism would itself be a euphemism. What had been a useful approach has been usurped by ideology.

Start with the meaning of "calm": It does not mean "slow". Think about being in a crowded room, and someone announces that there is a fire nextdoor and asks everyone to "calmly" move to the exits. Would you interpret that as telling you to be "slow" in leaving the room? If so, you deserve to die in the fire (joke). Calming is about removing jitters, of smoothing out motion and thereby making it more efficient. A major goal and benefit of traffic calming is to make movements of the vehicles more predictable, and thereby increase safety.

One of the basic observations of traffic engineering is that people have an intuition about how long it should take to get between two points. If they are slowed down in one segment of that trip, they unconsciously try to make up the time in subsequent segments. That also means that reducing congestion in one segment can reduce the inclination, or incentive, to speed in others. In the Caltrans/El Camino Design Study of the early 2000s, emphasis was given both to raising the speed in the slowest segments and to lowering the speed in the fastest, with a goal of not changing the overall end-to-end travel time for the corridor.

From presentations by traffic engineers that I attended before the term was usurped, the most intuitive counter-intuitive example was that stop signs have a potential for creating more collisions and injuries than they prevent. The first effect is that people accelerate out of the stop sign, resulting in both less predictable movement and in speeds between the stop signs that are greater than without the stop signs. The second effect occurs for stop signs that are put at intersections with little traffic: People become so accustomed to there being no cross traffic that their (rolling) stops become perfunctory, and eventually there is cross traffic that doesn't mentally register, even though that vehicle is perfectly visible.

Another counter-intuitive example that I have learned not to attempt to explain is provided by metering lights on freeway on-ramps. Briefly, for the average trip, the time you wait at the on-ramp is more than offset by the higher speed on the freeway (because it is operating near its maximum efficiency).

Old-style traffic calming involves the art of engineering (cost-effectiveness, tradeoffs ...), with heavy doses of experimentation and evaluation. Different measures that produce traffic calming can conflict in many situations, and the circumstances of a particular location rarely match the "textbook" version.

However if you look at the Traffic Calming page at the Institute for Traffic Engineers (ITE), you will see little of this. For example, there is a the goal "to reduce the negative effects of motor vehicles on the environment(e.g., pollution, sprawl)" and an objective of "encouraging water infiltration into the ground".

How does traffic calming promote the stated goal of "promoting...transit use"? Answer: If designed "properly" (sarcasm), it will increase congestion to a level where it is more painful than using transit.

One of the well-known problems of slowing traffic in one place is that of diverting vehicles to other routes. So where do these rank in the ITE objectives? Slowing is first; "reducing cut-through motor vehicle traffic" is dead last, including being after "water infiltration" and landscaping. Are those your priorities? Do you think this ranking should be the City's?

One of the goals of the original concept of traffic calming was to reduce driver stress and distractions as an important component of improving safety for everyone (drivers, passengers, bicyclists, pedestrians). In the usurped version, safety isn't even a goal, and is present only as an objective and even that is reduced to being measured by frequency and severity of collisions. Which version do you think the City should embrace?

So here we have the City asking for public input using a usurped term where the key word is totally unrelated to what City Hall is going to "understand" it as meaning. And they haven't provided any examples of what is and isn't meant by the term. If only there were a system where you could, you know, click or touch a phrase and get linked to additional and clarifying information. Just thinking out loud.

The big question to ask of City Hall is what is their explanation for using a term that they know is utterly deceptive if it isn't to pursue a dogma/ideology that doesn't have public support?
And if they claim that they don't mean what is written, ask why they keep saying what they don't mean year after year.

As to "GIGO" in the title, that is an Information Technology acronym for "Garbage In, Garbage Out".
For those who expect homage to the Ancient Greeks: The playwright Euripides wrote "A bad beginning makes a bad ending" and, on the flip side, Aristotle wrote "Well begun is half done".

An abbreviated index by topic and chronologically is available.

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I am particular strict about misrepresenting what others have said (me or other commenters). If I judge your comment as likely to provoke a response of "That is not what was said", don't be surprised to have it deleted. My primary goal is to avoid unnecessary and undesirable back-and-forth, but such misrepresentations also indicate that the author is unwilling/unable to participate in a meaningful, respectful conversation on the topic.

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Posted by Mark Michael, a resident of Community Center,
on Sep 17, 2015 at 8:57 am

Another thought provoking article from this blogger. I learned from the citation to the Institute for Traffic Engineers site. There is a link on that site to traffic calming measures: Web Link While the City's efforts at virtual engagement with residents is very well intended, the question could have been much better stated (i.e., more "pragmatic").

Not all Palo Alto neighborhoods presently have traffic calming measures and, thus, a question asking if your neighborhood benefits from traffic calming is lacking an important premise. So, perhaps two questions might have been more useful. For example, "if your neighborhood has traffic calming, are such measures achieving desired goals (e.g., improving safety, reducing speed, ameliorating congestion, deterring cut-through traffic, encouraging multi-modal usage, etc.)?" And, "if your neighborhood lacks appropriate traffic calming measures, what types of changes (e.g., speed bumps, traffic tables, closures, roundabouts, sharrows, pedestrian crossings, etc.) would you like to see implemented?"

Posted by Resident, a resident of Another Palo Alto neighborhood,
on Sep 17, 2015 at 8:59 am

The important thing to remember and most seem to forget is that the purpose of traffic engineering is to move traffic efficiently not to hinder its progress.

Lights being timed correctly is one thing that is very poor in town.

The sequences of lights on Alma are hindered by the grade crossings. How many times have I had my green to cross suddenly change to red without a car getting across because of an impending arrival of a train. Of course this has to happen to stop the cars but when the train has gone, why does the sequence still ignore the fact that traffic across the tracks have missed a turn?

Getting traffic around bottlenecks causes big problems. Alma/ECR/Sand Hill is a personal bug bear. To avoid this I use Churchill which is a bad intersection during school commute times, but there isn't a better option. Getting A/E/S sorted should be a priority.

How many cars on University and downtown are actually circling to find a parking space? Electronic signs showing how many spaces available in all garages and pay per hour machines will help those looking for all day parking. If I am going to an unfamiliar area I drive there and then look for parking. I never look on websites beforehand to look for complicated parking rules. Visitors to town will probably arrive here and get confused by our complicated system. Getting our parking situation simplified will do a lot to help traffic flow through downtown.

But getting traffic to where it needs to go instead of pretending it will go away is a fallacy that Palo Alto needs to get over.

Posted by sunshine, a resident of Barron Park,
on Sep 17, 2015 at 10:57 am

The statement in the last paragraph of "Resident of another neighborhood in Palo Alto" (immediately above this one) is the most appropriate.
"But getting traffic to where it needs to go instead of pretending it will go away is a fallacy that Palo Alto needs to get over."
Palo Alto Council and traffic engineers (how can they consider themselves engineers? That is like the high schooler at the soda fountain being called a soft drink engineer.) think that traffic will go away if they just push everyone to take busses or ride bikes. This will not happen.
That concept is great for 20-40 year old able bodied people without small children. Yes, I have seen the kid-carrier bikes. They neglect that a large percentage of those who live in PA are less abled and need a car to go to a store, especially if they want to bring home a bottle of milk and several cans of food. It's not on!
Council has allowed developers in many neighborhoods to remove good grocery stores from some areas.
Traffic calming should result in the cars being able to transit a given distance in the same amount of time at 8-10 am and 3-7pm as at midnight. This is not possible on Arastradero especially after all the traffic calming.
What needs to happen: 1. tell crossing guards to make students wait until a small group forms and can go across all at once. Often, now, the guard ushers each student individually across a street. Teach children to cross safely. Do not just say "they're just children"; 2. make the right most lane on north bound El Camino at Page Mill Right Turn ONLY. That lane will then be able to make the right turn and not be held up by people who will go straight; 3. enforce traffic rules for all--cars, trucks, bikes, pedestrians--with officers. Don't wait for someone to be killed; 4. enforce speed rules with officers. Now people speed all the time, even on busy residential streets with many bikers and pedestrians. I've recommended to officers whom I see parked on El Camino to set up a speed patrol on streets in my neighborhood. It never happens, at least not in my neighborhood, only on Embarcadero.
How many more can you think of?
Instead of wasting city money on traffic calming, use it to upgrade utilities, remove the utility tax, pave all streets so that there are no more pot holes and rough areas. Part of the problem in the area of rough areas is due to the city not insisting that work crews that put in plates over holes do not properly smooth out the edges.

Posted by mauricio, a resident of Embarcadero Oaks/Leland,
on Sep 17, 2015 at 11:07 am

mauricio is a registered user.

Traffic calming is a misnomer and a fantasy as well. Traffic volume is what we are dealing with. Palo Alto has a small town infrastructure. We don't have wide, multi lane boulevards and Avenues that can accommodate the kind of traffic that's moving through our arteries and city streets daily. Developers, irresponsible companies and bad politicians allowed Palo Alto to pretend it's a big city that can be the industrial and commercial center of the peninsula. The chickens have come home to roost and now we have to read about traffic calming in a traffic congested town, an entirely impossible task.

Posted by Curmudgeon, a resident of Downtown North,
on Sep 17, 2015 at 11:17 am

GIGO: Garbage In, Gospel Out

Posted by Douglas Moran, a Palo Alto Online blogger,
on Sep 17, 2015 at 1:15 pm

Douglas Moran is a registered user.

RE: Resident "why does the sequence still ignore the fact that traffic across the tracks have missed a turn?"

My recollection of meetings on this problem in the mid- to late-2000s is that it takes 4-6 complete cycles of the traffic light to get the intersection back to its normal efficiency after a train has passed. Because that efficiency involves synchronization of the traffic flows both parallel to the tracks and across the tracks, this is a complex problem.

From what the traffic engineers said, giving the cross-track traffic priority to clear that backup creates major problems for traffic along the tracks. A "damned if you do, damned if you don't" situation. The simulation software for traffic flows had long been good-enough to explore this and it was being used to determine how to time and synchronize the traffic lights, including different patterns during morning vs evening peak hours.

Posted by Tim Buck II, a resident of Downtown North,
on Sep 18, 2015 at 6:06 pm

You obviously view this from an engineer's vantage. Properly spun, responses to almost any question can be quite useful in the political world, which is where this survey abides.

Posted by new mindset needed, a resident of Another Palo Alto neighborhood,
on Sep 21, 2015 at 9:57 pm

Excellent article by Douglas Moran. It makes a very important point, particularly relevant to Palo Alto, the need to evaluate and understand the effectiveness and impacts of traffic calming and control measures. In this regard "Stop" signs are discussed. This is timely. Currently the City of Palo Alto is adding "Cross traffic does not stop" signs beneath "Stop" signs in a haphazard manner all over the City.This type of sign is normally used only in special situations where it is called for, not routinely. The result of what the City is doing is to create confusion along a corridor, since some intersections which are not 4-way stops have these signs and some do not. There is no logical pattern to it, no uniformity in the treatment. It also creates additional sign clutter along streetscapes, driver distraction as well as confusion. The end result is more dangerous streets.This is part of a general failure of the City to consider or even pay attention to the specific and broader impacts of what it is doing with respect to safety and neighborhood character. A new mindset is needed in Palo Alto City government.

Posted by Douglas Moran, a Palo Alto Online blogger,
on Sep 22, 2015 at 6:52 pm

Douglas Moran is a registered user.

To expand a little on "new mindset needed":

"Haphazard" deployment leads to unpredictability. In commenting to City Hall, it is useful to use both words to mutually reinforce the other.

Historical aside: I may be partially to blame. In the 1990s, I pointed out to the Transportation Division that there were so many 4-way stops that people were routinely surprised by the ones that were only 2-way. I made the observation that where I have previous lived, stop signs came with the annotation 4-way/all-way or 2-way/cross-traffic-does-not-stop. Shortly thereafter, there was a fairly extensive deployment of these additional warnings in the portions of town that mattered (northern Palo Alto). But something seems to have happened since (and I don't know what).

Similar situation: When roads narrow from 2 lanes to one, it is also haphazard/unpredictable whether it is the right or left lane that merges into the other, and signage far enough in advance is often lacking. I have pointed this out too many times, and the response that the who-merges choice seems obvious to the responsible party--unwilling to accept that others might have different intuitions.

Posted by new mindset needed, a resident of Another Palo Alto neighborhood,
on Sep 23, 2015 at 2:16 pm

@Douglas Moran
I think that the very selective use of "cross traffic does not stop" signs which is typically done, is the correct use of it. Since 100% coverage of all such intersections in a neighborhood is impractical at the least, something between "selective" very limited use as called for and total coverage becomes a no man's land, a twilight zone with a distracting and confusing message to drivers as they drive through a neighborhood which
is what we are doing here.

Deployment of signs has taken on a life of its own here. There is no sense
of any downside to more signs. Sign clutter, driver distraction, driver
response, neighborhood character- these are all non-issues, non-factors in consideration of traffic safety or livability in the City's one-dimensional world. To underscore this,take a look at the huge,industrial-sized "DIP" sign which just popped up at the corner of Waverley and Santa Rita.

Posted by Crescent Park Dad, a resident of Crescent Park,
on Sep 23, 2015 at 2:59 pm

I don't want to take this discussion off track - however I'd like to point out that Stanford has recently constructed traffic circles on Campus Drive at the intersections of Escondido and Bowdoin (it helps to have the real estate to open up the intersections to allow for this). IMHO these traffic circles are working out very nicely.

Posted by new mindset needed, a resident of Another Palo Alto neighborhood,
on Sep 23, 2015 at 9:19 pm

Just checked the National Academy of Sciences, Engineering and Medicines
in Washington, D.C. findings on use of "cross traffic does not stop" signs.
They say that increasing the use of cross traffic signs may cause drivers to expect them and to assume that in their absence all traffic must stop.
Use of the signs could cause drivers to expect them at all 2-way stop-controlled situations. "Expectations based on previous experience may affect judgment", "a driver may have subconsiously concluded that
intersections will have stop control". This is especially true if the street
has a certain type of roadway situation or look, which is what we are dealing with in our neighborhoods. So there is a definite caution here associated with what the City of Palo Alto is doing in its expanded use of the signs.

Posted by Douglas Moran, a Palo Alto Online blogger,
on Sep 23, 2015 at 10:29 pm

Douglas Moran is a registered user.

The basic principle I advocated was labeling all stop signs, either with "All way stop" or "Cross traffic doesn't stop" (or variants of the two). Then if there isn't a label, drivers should recognize that they need to fall back to the other/traditional ways of dealing with such intersections, such as looking for pavement markings on the cross street, or just waiting to see if cross traffic comes to a stop. As was pointed out, having a convention that the absence of one category of label cannot be used to imply the opposite. I know of many cities which do choose to put up primarily one type, and often in response to complaints rather than some more systematic criteria.

The additional labeling on stop signs is intended to improve efficiency of the intersections, not be a substitute for good sense by drivers.

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