Greater Greater Washington

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Speed camera bill now would make streets more dangerous

Tomorrow, the DC Council will take its second vote on its bill to lower speed fines. It's likely to pass, given that it passed unanimously on first reading, but it contains some extremely dangerous provisions, including one that would force the District to set speed limits based on the "engineering perspective" over neighborhood livability.


Photo by ph-stop on Flickr.

ANC 3E goes further and argues, in a unanimous resolution, that the bill would harm safety rather than enhance it. I have a hard time disagreeing, given that Chairman Phil Mendelson removed many of the important provisions in the original bill that came from the task force I served on, and added some harmful new ones.

I previously listed some troubling provisions that made it into the transportation committee markup, mostly at Mendelson's behest, but the most damaging is this section, which the committee didn't pass but which Mendelson added anyway:

(a) By November 1, 2013, the Mayor shall complete a District-wide assessment that evaluates the speed limits on the District's arterials and other streets. The report of the assessment shall include the criteria used for assessing the speed limits. Upon its completion, the assessment shall be posted to the District Department of Transportation's website. The assessment shall:
  • (1) Utilize factors common among transportation officials for the determination of speed limit;
  • (2) Evaluate whether comparable arterials should have comparable speed limits, and similarly do so for other streets;
  • (3) Include, based solely on an engineering perspective, speed limits for the District's arterials and other streets.
(b) By January 1, 2014, the Mayor shall revise, through rulemaking, existing speed limits throughout the District. The speed limits shall include comparable speeds for comparable arterials, and other comparable streets. Notwithstanding this requirement, the Mayor shall not cause an anti-deficiency as determined by a fiscal impact statement obtained by the Mayor from the Chief Financial Officer.
"Engineering perspective" shouldn't be only factor in speed limits

Mendelson apparently is trying to ensure that speed limits get set without regard for revenue or politics, and fairly between different arterials in various parts of the city.

Those are good instincts, but requiring an "engineering perspective" for speed limits is the wrong approach. The traffic engineering profession has a deeply ingrained practice of setting speed limits solely for car traffic, and with the motivation of making roads move traffic as fast as possible for the safety of drivers.

They traditionally use a simple "80% rule": Set the limit at the rate that 80% of drivers move on a particular road. The idea is that some people are speeding, but if most people travel at a particular rate, that rate is probably safe. And on a limited-access highway, that's not a terrible idea, because there is only one kind of road user (maybe two, if motorcycles are separate).

But our neighborhood streets, including arterials, have to balance the needs of many modes. 80% of drivers gives no thought whatsoever to the speed that will allow people to cross the street at unsignalized intersections (where it's legal) without the danger that a driver won't come around a curve so fast that they can't see the pedestrian or stop in time. It doesn't consider the traffic flow that would allow bicyclists and drivers to coexist safely and efficiently.

The "engineering perspective" doesn't have to ignore these factors; engineers could easily devise another algorithm that is better. But they generally haven't, and the guy in charge of speed limits for DDOT, James Cheeks, personally wrote a whitepaper when he worked for the Institute of Transportation Engineers advocating for the 80% rule.

That document says the 80% rule is "a case of majority rule." Actually, we often don't set laws just based on majority rule. We protect vulnerable minority groups and have legal processes to ensure majorities don't trample their needs. On the roads, motorists are the majority but pedestrians and cyclists are a vulnerable minority we need to protect.

At the task force meetings, Cheeks reiterated that the 80% rule was his preferred way to set speed limits, but when pushed, also added that DDOT always talks to residents and also thinks about pedestrian and bicycle safety. My fear is that the "engineering perspective" in Mendelson's provision will specifically push DDOT to follow the dangerous method in this whitepaper, which specifically comes from engineers, and not to incorporate other needs or listen to communities.

ANC 3E wants escalating fines

The Advisory Neighborhood Commission for Tenleytown, AU Park and Friendship Heights, ANC 3E, asked the Council to turn down the bill entirely, saying, "We believe the stated basis for enacting the Bill does not support the Bill's passage. Without material changes, we believe the Bill would fail adequately deter repeat offenders and lead to unnecessary deaths and injuries."

The ANC primarily is concerned that repeat offenders will get off easy for ignoring the laws time and again. The task force originally supported having some system that would give first offenders lower penalties, and chronic repeat offenders higher ones. The original bill also prescribed much higher fines for higher levels of speeding on the belief that traveling 20-30 mph over the limit is act much more intentionally flouting the law than speeding 11 mph over.

The ANC's resolution states:

ANC 3E believes the current fine regime, which per the legislative history puts DC near the middle of state fine regimes, is not unduly harsh. Evidence is strong that speed cameras save lives in DC. By contrast, the evidence is weak that higher fines do not promote more safety, as economic theory predicts, or that a majority of DC residents want to see fines lowered.

Whether or not the Council chooses to reduce some fines, however, we strenuously urge the Council to establish a system of fines for moving violations that escalates after a set number of offenses of a given severity. The escalation scheme should parallel the point system for violations in a police officer's presence. Thus, an owner whose vehicle is ticketed three times in a two year period for driving 16 mph over the limit should receive a fine on the third offense whose magnitude would be akin to the magnitude of license suspension for a 6+ months. Although we do not formally recommend such a sum, we believe that it should be at least $500.

If the Council does not amend the Bill to create such an escalating scheme, we respectfully urge the Mayor to veto it, and respectfully urge the Council to reconsider creating such a scheme.

The resolution also argues that absent more evidence that lower fines don't lead to more speeding, it doesn't make sense to lower the fines. It says that most residents do support the fines, and asks the Council not to listen to organized lobbying from a few special interest groups.

Update: Tina pointed out that this gem of a video is very relevant here. Everyone who thinks that the same old "engineering perspective" is the right way to make traffic decisions needs to see this.

David Alpert is the Founder and Editor-in-Chief of Greater Greater Washington and Greater Greater Education. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He loves the area which is, in many ways, greater than those others, and wants to see it become even greater. 

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"Engineering Perspective" is a wonderfully obscure piece of junk. Like David said, engineers could come up with a formula that incorporates other users but since there is no definition of how the Engineering Perspective is derived then why bother?

That means you just stick with "Comporable Speeds" and raise the limit since that isn't defined either and you just guess based on how fast you'd like to drive.

by drumz on Dec 17, 2012 11:17 am • linkreport

Engineering is a means of reaching an objective, not a means of setting an objective. An engineer can determine what speed limit will move as many cars as possible as fast as possible while limiting the number of crashes to some number considered tolerable. An engineer can also determine what speed limit will ensure that pedestrians are not seriously injured when struck by cars.

The phrase "engineering perspective" is being used here to conceal meaning, not to convey it.

by Ben Ross on Dec 17, 2012 11:26 am • linkreport

We need to get Mendelson (or his daughter) out of their car and out on a bike to navigate the city. Maybe the BicycleSpace Assembly or WABA can do this. If one moves recklessly around the city solely in a tank, one can easily become insensitive to those who walk or bike.

If Mendo is bullying his colleagues regarding committee assignments, so that they cannot speak up about rational policies, then he is unfit to be Chair and unfit to become Mayor. I think he's smarter than that, and has a record of working with his colleagues in a more cordial fashion. DC doesn't need a new, selfish small-minded tyrant in the Wilson Bldg.

But if he is considering committee shuffling, Mr Catania seems to be best suited to replace him on the Judiciary Committee and/or on the Finance Committee. For balance, it would be nice to see a woman as Chair Pro Tempore At-Large now that M Brown is out.

by BikeRider on Dec 17, 2012 11:28 am • linkreport

I've taken out the paragraph about committee assignments because after talking with some more folks, I think that that is one but not the only factor.

by David Alpert on Dec 17, 2012 11:37 am • linkreport

Our CMs clearly haven't been hit by cars travelling the speed limit.

by Survivor on Dec 17, 2012 11:40 am • linkreport

80% of drivers gives no thought whatsoever to the speed that will allow people to cross the street at unsignalized intersections (where it's legal) without the danger that a driver won't come around a curve so fast that they can't see the pedestrian or stop in time. It doesn't consider the traffic flow that would allow bicyclists and drivers to coexist safely and efficiently.

I don't know, going with the engineering perspective makes sense to me. While adhering to some airy-fairy standard about "pedestrian safety" may be fine for suburban neighborhoods, where people live, it makes less sense for the city, where people are trying to drive their cars to work in the morning, then drive home to where they live in the evening.

That's why 20 mph speed limits are common in suburban residential neighborhoods, but they're an outrage that must be opposed at all costs by organizations like the AAA if we're talking about DC.

Anyway, if people want to live somewhere where they can cross the street without being run down, why on Earth are they living in a busy city? They should be living in Reston or someplace like that. I'm just glad that DC's elected officials are able to see past the parochial interests of their constituents and do what's best for everyone.

by oboe on Dec 17, 2012 11:43 am • linkreport

If you can get engineers to come up w/any sort of algorithm, it should be easy to get them to come up w/something that doesn't solely rely on a 1+1=2 equation. DAL acknowledged that there is wiggle room there. We should use it.

I do not like the graduated penalty idea. Doesn't seem warranted here in DC.

Don't get the whole "committee assignment/fear the man" part.

by HogWash on Dec 17, 2012 11:48 am • linkreport

If we want slower roads we should stop designing roads for higher speeds. I don't have qualms with setting roads based on 85th-percentile (not 80) and 10 MPH pace metrics; but design should be the first and foremost tool for what brings those metrics into what is desirable for an urban pattern; not enforcement.

by Bossi on Dec 17, 2012 11:49 am • linkreport

Oboe, I read your whole post as snark, but the sad fact is many of our elected officials and leaders would not.

by Laurence Aurbach on Dec 17, 2012 11:51 am • linkreport

I think "engineering" should be construed as "impact of automobile on the structural integrity of the human body"

by SJE on Dec 17, 2012 12:43 pm • linkreport

Why don't you just go ahead and say what you want? What should the speed limit be according to you? 20? 15? 10? What is your basis for your conclusion?

By lambasting the proposed approach but not providing your own alternative, you're not helping.

by movement on Dec 17, 2012 12:57 pm • linkreport

Its fascinating how many of you are engineers....without an earned engineering degree. Today's engineers take in to account all modes of transportation, safety and mobility when making transportation decisions.

by BSCE on Dec 17, 2012 1:01 pm • linkreport

I think setting the speed limit to the 85th percentile (not 80th) as equal to the "engineering perspective" is the problem. This is not an engineering prospective; it is a statistical one, based on an arbitrary definition to deal with issues of unfair enforcement. That is, it is unfair to set speed limit lower than what people naturally want to drive.

The engineer would say if a given road encourages unsafe speeds, then the road should be redesigned to encourage the proper lower, safe speeds. Once that is accomplished, then the speed limit should be set to the 85th percentile speed.

by goldfish on Dec 17, 2012 1:16 pm • linkreport

@BSCE, I think you should see this.. http://www.youtube.com/watch?v=P9BUyWVg1xI

by Tina on Dec 17, 2012 1:45 pm • linkreport

We should design our lower speed roads to actually be driven at a lower speed. To do that for every road that needs in DC is a huge endeavor. Until then there needs to be a middle ground that can make the streets we do have a little safer.

Plus if you're complaining about non-engineers discussing engineering topics then you should also want a bill that better defines what an engineering perspective is.

by drumz on Dec 17, 2012 2:03 pm • linkreport

If a road were designed to force drivers to drive at a reasonable speed (say 25 mph on a mixed-use street) wouldn't that force transit and emergency vehicles to go much slower? That's my reluctance toward designing a street to the desired speed.

by Steve S. on Dec 17, 2012 2:10 pm • linkreport

@Oboe

People live in DC too. The roads you use to "trying to drive their cars to work in the morning, then drive home to where they live in the evening" are the roads where I live, and walk my dogs.

Also, regarding pedestrian safety, statistics say DC is a much safer place to walk then Reston.

by Kyle-W on Dec 17, 2012 2:11 pm • linkreport

Poe's Law in action again.

by AWalkerInTheCity on Dec 17, 2012 2:15 pm • linkreport

@Tina,

That is one of the most pejorative videos I have ever seen. It likens engineers to mindless bureaucratic robots that have no perspectives on pedestrian safety. No engineer is that bad.

In another thread today there is a debate about calling a certain member of the DC city council "the woman". Sound to me like according many, it would have been worse to call her "the engineer."

by goldfish on Dec 17, 2012 2:16 pm • linkreport

Steve S,

While I'm not saying it should be outright ignored the main thing that impedes transit and emergency vehicles in the city would seem to be the traffic in general rather than the width of the road.

Kyle-W,
Check Oboe's post history. He's being very sarcastic.

by drumz on Dec 17, 2012 2:21 pm • linkreport

@goldfish - no funny-bone?
Try this: http://www.strongtowns.org/journal/2010/11/22/confessions-of-a-recovering-engineer.html

by Tina on Dec 17, 2012 2:53 pm • linkreport

@Tina: my funny knob was at "11" and it still did not take. It was stupid. More to the point, it is astonishing that some people would find it funny, which paints all engineers as dolts. Substitute any other profession and you see how insulting it is. You could not get away with portraying dentists that way, for example.

by goldfish on Dec 17, 2012 2:58 pm • linkreport

ANC 3E goes further and argues, in a unanimous resolution, that the bill would harm safety rather than enhance it.

Honestly, just because an ANC says something doesn't make it true. In fact, I'd be less willing to trust the opinion of an ANC vs. other policymakers.

Also, the hate for engineers is coming from you guys simply because you're jealous that they can do math but you can't.

by JustMe on Dec 17, 2012 3:03 pm • linkreport

Traffic and road engineers should be required to live car-free for a year as part of their training. Currently they are impediments to sane roadway work in the my part of the suburbs, I can attest to that. They've turned Greenbelt roads into ugly speedways and over-wide, person hostile strips, and they push back (read the draft Route 193 master plan) hard and effectively when the surrounding communities recommend saner, more person friendly approaches. Engineers hate people, love cars. Period.

by Greenbelt on Dec 17, 2012 3:03 pm • linkreport

@goldfish-it was written by an engineer. Take a look at his "Confessions". He publicly made fun of himself and let us in on the joke, and you are really offended by that.

by Tina on Dec 17, 2012 3:06 pm • linkreport

What should the speed limit be according to you? 20? 15? 10? What is your basis for your conclusion?

In areas with significant numbers of peds, the basis should be your chance of getting killed if hit by a car traveling the speed limit. Over 25mph, your chance of dying skyrockets.

by Falls Church on Dec 17, 2012 3:06 pm • linkreport

@goldfish - Never heard a lawyer joke?

by Ben Ross on Dec 17, 2012 3:07 pm • linkreport

Keep in mind that the most ridiculous camera-enforced-speed-limit excesses involve a 40-mph limit ON AN INTERSTATE HIGHWAY. I'm a bicycle commuter and big on walking, but I don't pedal or stroll on I-395.

by Elliott Carlin on Dec 17, 2012 4:20 pm • linkreport

I fail to understand how increasing the speed limit on 295 or 395 is going to make things "more dangerous" for biking and walking.

by ceefer66 on Dec 17, 2012 4:48 pm • linkreport

Goldfish, apparently I viewed the video differently than you. Rather than it being a pjorative toward engineers, I saw it as a goverment bureaucracy trying find a way to "make work" to justify their bureau and job. I some of those happened to be engineers, then so be it.

Lynn

by Lynn Jackson on Dec 17, 2012 6:33 pm • linkreport

The picture of the formula one race car is a nice touch.

Not that it has anything to do with DC speed limits.

by ceefer66 on Dec 17, 2012 7:44 pm • linkreport

There's an unfortunate willingness to buy the notion that speed cameras, and more stringent speed limit enforcement, "saves lives". That may well be true out on open-highway-land, but it isn't necessarily so here in the city. The advocates of speed cameras base their arguments on that assumption, without seriously questioning it.

See http://dcjack.org/photo%20enforcement.html . No, speed cameras in DC are NOT saving lives. And if you drop that assumption, then what's the point?

by Jack on Dec 17, 2012 8:48 pm • linkreport

Adding a little more evidence to my thesis that speed cameras in DC are not, contrary to widespread belief and MPD assertion, saving lives:

DC traffic fatalities (NHTSA data):
2007: 44
2008: 34
2009: 29
2010: 24

Nice decrease, certainly! The MPD, and the people on that speed limit panel, immediately conclude that this decrease due to speed cameras. But wait -- how many of these fatalities are "speed related"?
2006: 3
2007: 8
2008: 12
2009: 10
2010: 8
See any decrease? Nope. Because traffic fatalities in DC have little to do with automobile speeds. Hence, more stringent enforcement of speed limits -- higher fines, for example -- will NOT save any lives.

by Jack on Dec 17, 2012 8:55 pm • linkreport

See http://dcjack.org/photo%20enforcement.html . No, speed cameras in DC are NOT saving lives.

It seems that they are. The author of dcjack.org simply asserts, "well it COULD be that something ELSE is causing the drop in fatalities! What about THAT?"

by JustMe on Dec 17, 2012 8:57 pm • linkreport

Even if speed cameras aren't saving lives (perhaps they're reducing non-fatal injuries of pedestrians and cyclists?) even so, they're effectively a tax upon reckless @$$holes; better to tax them than sales, incomes or property.

by Steve S. on Dec 17, 2012 10:37 pm • linkreport

@David, I am sad that you seem myopically focused on making all of DC go at a walking pace. I live here too. I run, bike, bus, and (horrors!) drive to work and around town. I hate commuting time. I hate neighbourhood a that impose stupid-slow limits (20mph on Military near CT). Moving to an engineer-based mph limit is wonderful. If it means 45 on 16th north of rock creek, then woohoo!

Now if we could get rid of speed humps...

by Wayan on Dec 17, 2012 10:43 pm • linkreport

I hate neighbourhood a that impose stupid-slow limits (20mph on Military near CT).

So...where exactly is Military Rd 20 mph? I thought the minimum speed limit in DC was 25 mph (which, of course, means 30 mph).

by oboe on Dec 17, 2012 10:51 pm • linkreport

@Tina: fun of himself and let us in on the joke, and you are really offended by that

So you now use this to subvert the good intention behind the legislation, i.e., to have engineering set the speed limits according to safe operating speed based on road design, compared to the universally acknowledged "revenue grab" in current use. Real funny.

by goldfish on Dec 17, 2012 11:34 pm • linkreport

If it means 45 on 16th north of rock creek, then woohoo!

There is no place on 16th in DC where driving 45mph is safe. Houses and sidewalks along the entire stretch.

@goldfish
Except "engineering standards" doesn't mean "safe operating speed based on road design" and it sure as hell doesn't mean "safe operating speed FOR ALL USERS."

by MLD on Dec 18, 2012 8:23 am • linkreport

@MLD: as it stands right now, "engineering standards" does not mean anything because, as I am sure you realize, standards are normally defined and/or then cited, such as they are in contracts (e.g., ASTM; MilSpec). No such definition or citation was offered.

Nevertheless, I think there is wide public agreement with the intent of the legislation, namely to make speed limits less political and less about revenue and more about safety -- for all, not just motorists, btw -- from a strict engineering point of view.

by goldfish on Dec 18, 2012 8:51 am • linkreport

@Drumz

I will admit, I stopped reading after the first paragraph. My mistake. I was confused as well, considering the source :)

Anecdotally, as someone who drives to work from Petworth to Bethesda, on roads with tons of speed cameras, I see people doing the speed limit, even past the speed cameras.

Works for me.

by Kyle-W on Dec 18, 2012 9:18 am • linkreport

@Oboe: over-sized 20 or 25mph signs on westbound Military just after exiting rock creek and passing the big private school. there is even a specific street cutout parking space just for MPD cruisers to sit and speed camera the hill. That speed limit is pure community activism vs. practicality, street build or necessity. Military is a major x-town artery!

@MLD: people drive 45mph every single day along 16th north of rock creek and we do not have fatalities or pile-ups, so yes, its actually safe. Now it may not be as safe as going 30, but 30 is not as safe as banning cars and making everyone walk up and down 16th - the logical conclusion of slower = safer.

Oh wait, if we did that, folks would have heart attacks and heat stroke in the summer, so it might actually be more dangerous than driving 45mph.

by wayan on Dec 18, 2012 9:30 am • linkreport

people drive 45mph every single day along 16th north of rock creek and we do not have fatalities or pile-ups, so yes, its actually safe. Now it may not be as safe as going 30, but 30 is not as safe as banning cars and making everyone walk up and down 16th - the logical conclusion of slower = safer.

Except the argument isn't "we should have slower at all costs because slower=safer." The argument is we should balance the safety of all users against the time of drivers. And a lot of us think it's too far tilted towards the drivers' concerns.

Also, where the heck is "16th north of rock creek"? The park goes all the way to the District line.

by MLD on Dec 18, 2012 9:33 am • linkreport

How the Brits are doing it
Here are links to new (July) guidance docs and web tool from the UK"s Dept. for Transport on "Setting Speeds on Local Roads"
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/2733/setting-local-speed-limits.pdf

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/2732/consultation-document.pdf

also, from the European Transport Safety Council's "Speed Monitor" Nov2012 newsletter there's a review (pg.7) of a recent UK report on "Speed and Safety:Evidence" which talks about the UK's +3,000 speed camera sites. link below
http://www.etsc.eu/documents/Speed_Monitor_12.pdf

by Larry Shaeffer on Dec 18, 2012 9:46 am • linkreport

@MLD 16th north of Piney Branch, the only time 16th crosses Rock Creek Park proper vs. abutting it

by wayan on Dec 18, 2012 10:50 am • linkreport

@MLD: I am for a balanced approach to speeds - faster speeds on main thoroughfares, slower speeds on side streets. 16th is a main artery - it should have a higher speed than Juniper or Newton side streets. Say effective speeds of 45/30 (vs. posted & ignored speeds)

by wayan on Dec 18, 2012 10:54 am • linkreport

I am for a balanced approach to speeds - faster speeds on main thoroughfares, slower speeds on side streets. 16th is a main artery - it should have a higher speed than Juniper or Newton side streets. Say effective speeds of 45/30 (vs. posted & ignored speeds)

And screw the people who live there, so you can get home 2.5 minutes faster? Yes, that is the difference if you drove 30MPH from piney branch to the dc border vs driving 45. 2.5 minutes. And it doesn't include stoplights, so I assume you wouldn't even gain 2.5 minutes.

Also I don't understand the "posted & ignored" argument. Wouldn't these new speeds be ignored just as much? So wouldn't people be driving even faster than the limit still?

by MLD on Dec 18, 2012 11:14 am • linkreport

@Wayan

I also drive on 16th, albeit North in the morning, and South in the evening, and see no one doing 45. I am quite comfortable doing 30, and feel it is an appropriate speed for that section.

The fact you are doing 45 has reminded me that I have been intending to e-mail my councilmember (Bowser) asking for more cameras on those sections, which I have just done. Thanks for the reminder!

by Kyle-W on Dec 18, 2012 12:05 pm • linkreport

@MLD: And screw the people who live there, so you can get home 2.5 minutes faster? Yes, that is the difference if you drove 30MPH from piney branch to the dc border vs driving 45. 2.5 minutes. And it doesn't include stoplights, so I assume you wouldn't even gain 2.5 minutes.

A fine example of adding heat instead of light; that is the problem. One the one hand there are residents that see oblivious drivers bombing through past their house with kids playing outside, and on the other hand there are drivers that see gotcha! speed cameras on roads with no pedestrians with speed limits clearly lower than the speed that 95% of what people drive, with confiscatory fines. And both sides yelling past each other.

Lowering the temperature is what is called for, and that is just what engineers do.

by goldfish on Dec 18, 2012 12:13 pm • linkreport

David, when do you use "engineering perspective" as an epithet? When I was a practicing engineer in a local public agency, we used engineering JUDGMENT to lower speed limits from the state agency mandated use of the 85% speed of traffic. Engineering judgment (or perspective) allows an agency to incorporate all those issues (schools, pedestrians, parking, bicycles, access point, transit vehicles, sight distance, etc. )into a speed study and not be forced to follow a specific statistical standard. That is a good thing, prescriptive standards make a bad environment for and urban right-of-way. It also provides some level of protection from the tort liability attorneys, because an engineer (specifically a licensed engineer) has authority to make decisions for the built environment to "safeguard the life, health, and property and promote the public welfare." (that is right out of DC licensing rules in the DC Register). When an engineer in DC (and elsewhere) is following the requirements for their license he/she will be doing everything you are asking for.

by Some Ideas on Dec 18, 2012 2:08 pm • linkreport

1. We're not talking about all engineers, just civil engineers. And everyone knows that civil engineers are the fluff girls of the engineering world.

2. As a Master of Engineering let me say that the problem is not one of engineering perspective it is one of requirements definition. If you ask the engineer to make the road safe for all users and define the metrics that would constitute that - and define good requirements - then you'll get a safer road. Also, if you can write good requirements then you'd be the first person I've ever met who can.

3. The requirements here seem to be to use two values to create an isoquant using speed and driver's sense of safety as the inputs. Both of these are wrong. Speed is being used as a proxy for throughput and driver's sense of safety as a proxy for safety. But moving cars faster does not always increase the throughput of people. And driver's sense of safety is wrong twice. One - because it ignores other users and two because people are very bad at estimating risk. Most people find roller coasters scarier than driving, even though the former is much safer than the latter.

4. The solution is to use better inputs. Determine the throughput of people at various speeds. Determine the safety of driving at various speeds. Plot those out and then rationalize the trade off between moving people and protecting them in a way that you can define and explain. That's how I'd do it.

by David C on Dec 18, 2012 5:06 pm • linkreport

If highway safety is the motivation for ATE, then enforcement should be a deterrent to further speeding, thereby improving safety. The mere fact that some locations issue more than ten tickets an hour 24/7 demonstrates either no deterrent effect or highways full of inconsiderate, unsafe drivers with lots of money. A rational, reasonable person cannot explain the consistently high number of tickets being issued month after month, year after year.

If ATE was effective, drivers would slow down and the number of tickets would decline. No rational test would confirm that there are that many unsafe drivers racing through the streets of DC endangering public safety. Most safe drivers evaluate the road conditions as the determining factor in their speed, not some errant sign posted not following an 80% engineering rule of thumb. No officer of the law would issue a ticket where speed limits are obviously miscalculated, as many know first hand.

ATE is based on fallacious reasoning, except that it does generate a lot of revenue for the district. To be totally safe, just outlaw vehicular traffic on DC roads. But we accept risks in order to save time. Speeds too slow create more accidents, speeds too high create more serious injuries. There has to be a rational median and a workable method of containing the faster drivers that present too high a risk for the rest of us to assume.

by rkirkr on Dec 18, 2012 9:05 pm • linkreport

@David C "...civil engineers are the fluff girls of the engineering world..."

Hmmm... if that were really so I don't think I would leave the ground, let alone 40+ some stories in an office building or walk across a bridge...

If they were all that "fluff" then we would be living in huts and drinking our own sewage.

At least the military gives them some credit, "Civil engineers build targets."

by Some Ideas on Dec 18, 2012 11:57 pm • linkreport

But he's right that speed limits have been decreased to increase traffic fines. It's particularly troublesome on limited access highways where our safety on bicycles really isn't an issue.

It's a tough question because you want to preserve safety while also keeping traffic moving. I bike commute 65% of the year, metro 30% and drive maybe 5%, yet I do think some DC road speed limits are ridiculous. For example the stretch of North Cap by the hospital, 395 coming from New York Avenue, etc. I mean, I've seen alley speed limit signs in DC that match some road speed limits.

It's not the speed that worries me with drivers since I don't forsee DC deciding overnight to make something like L Street a 45mph road, it's the police attentiveness. I would rather some vigilance from the fine officers of the law toward all the retards who run reds, block the box or otherwise make ridiculously stupid decisions in traffic that don't help them get anywhere faster yet nearly kill me in the process. I mean screw speed cameras, block the box cameras would do a lot more to help my safety.

by T1 on Dec 19, 2012 3:18 pm • linkreport

Simon Washington, the Arizona State University engineering professor who co-authored the report, found that the speed camera program “not only improved safety but also improved mobility through travel time savings, improved travel time reliability, and reduced travel time uncertainty.”

The report found that during the nine month speed camera trial program
mean traffic speeds were reduced by nine mph
total crashes were reduced by 44% to 54%
injury crashes decreased by 28% to 48%
The annual estimated safety benefits ranged from $16.5 to $17.1 million, based on medical costs, quality of life costs and other costs (lost productivity, wages, long-term care, etc.).

From: http://www.azdot.gov/TPD/ATRC/publications/project_reports/PDF/AZ684.pdf

by Barry Childress on Dec 21, 2012 10:20 am • linkreport

That AZ684 study has been debunked as a marketing scheme by and for the cameras' manufacturer, Redflex. Biased to prove a point, or make a sale. Objective multi-variable studies have shown otherwise. See aged comments linked:

http://veilguy.blogspot.com/2009/07/photo-enforcement-safety-benefits.html
http://veilguy.blogspot.com/2009/07/intelligent-transportation-systems-safe.html

I think the article above, "Speed camera bill now would make streets more dangerous," tries to make the point that engineers are wrong in their analysis. The critics claim that drivers need to be more responsible, meaning no speed is too slow. The more learned, engineering related comments here tend to allow the many aspects associated with road safety determine acceptable speeds, albeit not perfect, at least more in line with law enforcement everywhere else.

There are two sides of course trying to influence decision makers. Do they go for popularity? Or do they offer rational reasoning to do what is right for everyone? First thing is to make sure everyone knows the rules specific to DC. Road designs and driving conditions have to be part of the calculus, instead of posting miscalculated speed limits and take in more money (bonus!). Safe drivers adhere to their common sense driving skills watching out for the other guy, not some errant signs. Gotcha! and the tens of thousands other drivers on the road with you.

ATE simply has not worked. I believe officials feel guilty for taking money from car owners this way without showing intended results. Lowering fines is no substitute for doing the right thing.

by rkirkr on Dec 21, 2012 4:33 pm • linkreport

Some ideas,
1. I was kidding. Civ-Es are great. My dad was sort of one
2. You should google "fluff girl", but not from a work computer.

by David c on Dec 22, 2012 5:52 pm • linkreport

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