Underlying this column is the assumption that posted speed limits indicate a maximum safe speed, and anyone exceeding those limits must be putting the public at risk. Where's the evidence for that assumption?

Fact: speed limits in DC are set well below any maximum safe speed, to account for the policy of allowing up to 10 mph over the posted limit.

Also fact: on most commuter routes, the average speed of traffic is higher than the posted limit. That is, the great majority of drivers "speed", simply to keep up with the mean pace of traffic.

What David advocates is a forced slowing of all traffic in DC, even though the connection to actual safety is no more than an instinctive assumption. And people here are not, with rare exception, speeding for thrills, but simply to get where they are going in a reasonable amount of time. As a 2006 DDOT study reported, drivers really don't want to get into accidents, so they judge the speed that will get them to their destinations in as little time as possible, but without collisions.

The MPD wants to turn DC into a police state, an automated traffic cop on every corner. If speed limits were sensible, that would be tolerable. But they're not.

by Jack on Oct 13, 2012 10:57 am • link • report

Automobile manufacturers label the speedometer vaguely and make many of their automatic transmissions awful hard to keep cruising at or under 25 or any other commonly posted limit. Motorists, having paid steeply for the wheels, are caught in the middle when the government declares the cars' natural behavior illegal. The speed limit is blunt and arbitrary, but the hysteria against enforcement, by people who are in no special hurry but cannot manage to avoid speeding, stems from helplessness and shame.

How about a feature whereby the driver could acquaint the auto with the limit (as if setting cruise control) and then the car would require an extra heavy or sudden foot on the pedal to cross that threshold, e.g., for an evasive maneuver?

by Turnip on Oct 13, 2012 11:25 am • link • report

I've paid 1000 bucks in speed camera tickets and tickets from officers. This is clearly an effort to make up a budget gap caused by social programs not connected to welfare-to-work requirements. I resent this redistribution of my wealth to the city.

by Joe Shmoe on Oct 13, 2012 12:04 pm • link • report

Jack asked for evidence about speeding. Our government collects a large amount of data about crashes and speeding. The research literature from government, business, and academia is extensive. We know for example that nationwide in 2007, speeding crashes accounted for 31 percent of fatal crashes and 13,040 people died in speeding crashes.

Source:
http://www-nrd.nhtsa.dot.gov/Pubs/810998.PDF

In Maryland from 1998-2004 speeding was responsible for 20% of all crashes. Exceeding posted speed limit was responsible for 20% of injury crashes -- about 1,950 per year. Exceeding posted speed limit was responsible for 58% of fatal crashes -- about 135 per year.

Source:
http://www-nrd.nhtsa.dot.gov/Pubs/811090.PDF

In response to Turnip, low posted speeds of 10-25 mph are commonly found in residential areas, school zones, lanes, and parking lots all around the country. If anyone finds they are having difficulty driving at those speeds, they certainly should get driver training assistance and/or obtain a vehicle which they are able to control properly.

by Laurence Aurbach on Oct 13, 2012 12:37 pm • link • report

Correction, I'll rephrase that.

In Maryland from 1998-2004 speeding was responsible for 20% of all crashes. There were two types of speeding: "driving too fast for conditions" and "exceeding posted speed limit."

Exceeding posted speed limit was responsible for 20% of speeding-related injury crashes -- about 1,950 per year. Exceeding posted speed limit was responsible for 58% of speeding-related fatal crashes -- about 135 per year.

by Laurence Aurbach on Oct 13, 2012 12:47 pm • link • report

Good article, David.

One aspect that is missing from the debate, and that I would have expected to see is road design. I was recently out of the US in a place where speed limits were very poorly posted. However, I found that the roads had been designed such that speeding was pretty much impossible.

To get rid of speeding, we need much better designed roads. We need narrower lanes. We need more roundabouts. We need wider side-walks and better posted pedestrian crossings.

by Jasper on Oct 13, 2012 1:35 pm • link • report

I have to agree with Jack on this one.

DC's posted speed limits (plus the unposted, default, speed limit of 25mph) are often unreasonably low. And I don't think most people drive 30mph in a 25mph zone for the "momentary thrill" of it.

by nativedc on Oct 13, 2012 1:37 pm • link • report

25mph is not an unreasonably low speed limit. Certainly not for city streets.

The ten mph cushion for enforcement is because you must prove that e violation actually occurred. The problem is that our methods of measuring speed are all rather imprecise. Your speedometer in the car is not exact, nor are radar guns. Thus, by setting the threshold higher, you ensure that the measured speed, even when accounting for uncertainty and error, is actual proof of exceeding the speed limit.

by Alex B. on Oct 13, 2012 1:55 pm • link • report

Given that many DC streets display a delta between the posted speed limit and the actual maximum safe speed based on the roadway's design and configuration--see Porter Street NW at Rock Creek for an example--I tend to be skeptical of blanket statements asserting that exceeding the posted speed limit is "responsible" for x percent of crashes.

As a trained urban planner and a former law enforcement officer with experience investigating crashes, I agree that it's imperative for drivers to understand that excessive speed is a factor in many crashes, and that higher speeds generally mean greater injury/fatality and property damage potential in a crash. But it's equally important for us to remember that correlation is not causality. Extreme excessive speed (i.e., speed that is truly unsafe within a given set of roadway design and condition characteristics) can certainly lead to a crash in and of itself; that said, most crashes aren't caused solely by driving above the limit, as an earlier commenter asserts. Indeed, there are usually multiple precipitating factors in play, such as driver distraction, mechanical failure, or environmental conditions.

I don't think this discussion is really just about people wanting to drive fast in DC. Antiquated signalization practices and excessive use of uncaveated right-turn prohibitions provide two additional points of evidence that there are systemic problems with how traffic is regulated in the city. Examples abound of intersections where the signals could safely be set to flash during low-traffic hours but are not; similarly, the District is positively infested with "No right on red" signs posted at intersections that lack the pedestrian activity, sight line obstructions, or other characteristics needed to justify such a control measure, and where such a measure is actually needed to manage potential conflicts, I have yet to see a "when pedestrians present" or other appropriate caveat applied.

Drivers do have a responsibility to obey traffic control devices. But an equal burden is on planners and engineers to make sure that these devices are not deployed in an arbitrary, half-baked manner. And if enough citizens are actively challenging the validity and legitimacy of a device, perhaps the blame for non-compliance isn't exclusively on the drivers.

by Shawn F on Oct 13, 2012 2:25 pm • link • report

Minor nitpick: you say "Studies have found that 80 to 93 percent of drivers believe they are above average in ability. Mathematically, this isn’t possible." That isn't really true. Imagine ten drivers which have been scored in driving ability on a hypothetical 1-10 scale. Eight are reasonably good drivers, getting a score of 8/10, and two are abysmally bad, with a score of 1/10. The mean (what most people interpret "average" to mean) score is 6.6/10, and 80% of the drivers in this group (all the ones who scored an 8/10) are thus above average. It's true that it would be mathematically impossible for 80% of drivers to be better than the *median* ability, but that's not what was asked.

I don't think this really has any bearing on your underlying point, though I wouldn't be the least bit surprised if the real distribution of driving is skewed away from normal (that is to say, mostly decent drivers offset by a few very bad ones). It's probably not as extreme as in my hypothetical, nor exactly matching people's opinions of themselves, but it may well be that more than half of drivers are above average.

by Andrew Pendleton on Oct 13, 2012 2:50 pm • link • report

Driving at 40+ on a 25mph street seems safe if you are concerned about the ability to control the car or to avoid other cars. Your chance of being killed as the driver is probably quite low. Most "safe driving" is determined by the engineering for the car on the road.

What seems to be forgotten by Courtland Milloy et al is that 25mph is a maximum safe speed in an area where there are lots of people, because the chance of killing someone rises rapidly once you go beyond 25mph.

DC is a dense urban environment, with lots of people, including tourists and foreigners who may not be accustomed to the area or culture. More children and cyclists. More people are driving smaller cars.

25mph is not unreasonable speed when you have to consider how your actions impact others.

One thing I would like to see is that the fines be matched to the underlying speed. Driving at 70 in a 55mph zone is nothing like driving 40mph in a 25mph zone, yet the fines are typically the same.

by SJE on Oct 13, 2012 3:07 pm • link • report

The problem here is that many drivers here suffer from the "windshield perspective". They only perceive that they think is safe, without paying any regards at all to other road users, and what they might feel about safety.

The problem is that many roads are simply too wide and invite speeding. Drivers feel safe because there is plenty of space for them on the road. That space however, creates a problem for pedestrians and bikers, especially those crossing the road. They must often run for their lives to avoid drivers who come at them speeding, all feeling safe on this wide road and surrounded by a ton of steel. On some curvy roads, you can't even see each other coming around a corner.

by Jasper on Oct 13, 2012 3:11 pm • link • report

The biggest irony, of course, is we've set up an alternative system of cameras all around the region. Of course they are being used for other nefarious purposes (revenue among them).

And again, another op-ed by D. Alpert that refuse to admit the traffic speed limits are being set artificially low -- for example on NY Ave, or 295 (40 MPH).

I'd find this a lot more credible if, for instance, we called for better speed limits and enforcement within cities in return for loosening highway speed limits

by charlie on Oct 13, 2012 4:27 pm • link • report

Charlie: can you point to any engineering studies that demonstrate that the speed limits are "artificially low" on those streets, or point to a comparable street with a higher limit?

Not sure where you are talking about on NY Ave: it is a major arterial, but that doesnt mean it should have a faster limit, because a lot of NY Ave is narrow, in a neighborhood, with lots of cross streets. Most of my delays on NY Ave were because of accidents, suggesting that that other drivers also thought that the speed limit was too low, but were proven wrong.

by SJE on Oct 13, 2012 4:55 pm • link • report

@SJE

I'll tell you what part Charlie is talking about: east of Bladensburg, New York Avenue is a four-lane highway that travels through an almost unpopulated area of D.C., with little if any pedestrian activity and only one cross street that I can think of (and that's an off-ramp to the Washington Times building, used by very few people).

Eastbound, the speed limit is 40 (it used to be 35, until enough people complained). There sometimes is a mobile speed camera there in the service lane between New York Avenue and the Arboretum, but by now it's almost wholly ineffective: It's visible from a long way down the road, so people stay at the speed limit until passing it and then gun it.

Westbound, the speed limit is still 35.

by CapHill on Oct 13, 2012 5:13 pm • link • report

"most crashes aren't caused solely by driving above the limit, as an earlier commenter asserts. Indeed, there are usually multiple precipitating factors in play, such as driver distraction, mechanical failure, or environmental conditions."

Shawn F, you're right that to be perfectly correct I should say driving above the speed limit is a contributing factor in most fatal crashes.

But it's important to recognize the additional factors you mention are more lethal at higher speed. At higher speed, there's less time to perceive and correct for driving errors or mechanical failures. Bad environmental conditions, which factor into the "driving too fast for conditions" category of speeding, are also more lethal at higher speed.

I agree that better signal timing and synchronization could do a lot to make DC traffic smoother, safer, and less aggravating. Maybe if traffic signals were synchronized intelligently, people would feel better about driving at posted speed between the signals.

by Laurence Aurbach on Oct 13, 2012 6:26 pm • link • report

Montgomery County's posted speed limits are ridiculous. 35 mph on 6-line, divided arterial roads like Connecticut and Georgia? When the nearby secondary RESIDENTIAL two-lane roads are set at 30?

There's absolutely no way that driving 47 mph on a Saturday morning down an empty Georgia Ave. merits a speeding ticket. No police officer would ever ticket it, because they'd be driving the same speed.

Set a reasonable speed limit, and there's no problem.

But with these artificially low speed limits, these cameras are revenue-generators, pure and simple. Like the cameras on DC-295, keeping the world safe from people driving 67 mph on a freeway.

It would be equally ridiculous to install cameras on the always-wide-open ICC without setting a more reasonable speed limit. It's nonsensical to claim that such things are about public safety.

by JayTee on Oct 13, 2012 8:24 pm • link • report

@Laurence Auerbach: You say the NHTSA data shows "speeding was responsible" for (some %) of crashes.

That is incorrect. It says that in the crashes, the driver was speeding. It's absolutely invalid to say that the coincidence of two events means one is the cause of the other. That is why the NHTSA explicitly refers to "speeding-related" -- while you can say for sure that a driver in an accident was speeding, you really can't say for sure that it's the speed that caused the crash.

In fact, without knowing what percentage of drivers in a given situation are speeding all the time, that information is completely useless. If 20% of the time, in a crash, drivers are speeding, but people speed 30% of the time, what would that say? That speeding makes you safer, apparently! But that information is not part of the data you present. So we can't draw any conclusions about the relationship between speeding and accident causing, unfortunately.

Beyond this, the NHTSA data is almost completely irrelevant in DC. Most traffic deaths occur at highway speeds. We have few highways in DC.

Finally, if I am not mistaken, we're concerned about pedestrians, not the occupants of cars. The NHTSA data does not differentiate.

by Jamie on Oct 13, 2012 9:47 pm • link • report

Jaytee - Connecticut and Georgia (south of Bel Pre Road) Avenues are major bus corridors with numerous unmarked crosswalks -- every few hundred feet on much of Georgia. (Under Maryland law, there are unmarked crosswalks at both sides of every intersection that does not have a traffic light.) The buses run from before dawn until after midnight. There are plenty of bus riders on Saturday morning -- the road is not empty, even when cars are absent.

As a driver, it is your legal obligation to stop your car and yield to pedestrians who are using the unmarked crosswalk. It is your legal obligation to carefully watch for pedestrians on both sides of the road and stop your car when a pedestrian attempts to cross in the crosswalk (marked or unmarked).

When I drive, I find it taxing to comply with the right-of-way laws on a road with the numerous unmarked crosswalks and heavy pedestrian traffic of Georgia Avenue, even in daylight, at 30 mph. I don't think it's possible at 30 mph at night, certainly not at night in the rain. And it's utterly impossible under any circumstances at 47 mph. Under these circumstances, it's no surprise that there have been numerous pedestrian fatalities on Georgia between Wheaton Metro and Bel Pre Road.

The speed limit is a maximum. When it isn't possible to drive legally and safely at the speed limit, the law requires you to go slower.

*** And if your argument is that Georgia Avenue is badly designed, and should be rebuilt so that it doesn't encourage driving at unsafe speeds, I agree entirely. ***

by Ben Ross on Oct 13, 2012 9:58 pm • link • report

What folks forget is that a drivers natural tendency is to drive in a way that's safe for them and other drivers. The fact that drivers are surrounded by two tons of steel and an array of safety gizmos means that the speed that's safe for them and other drivers, is not safe for pedestrians with no protection. Pedestrians and bikers are why DCs speed limits are set at 25mph.

The other reason is that no one likes to live or walk on a street with high speed traffic whizzing by. Since many of DC and even suburban streets are dense with residences and people walking to and from destinations or bus lines, it makes sense to set speed limits that do not only consider the needs of drivers.

What if the tables were turned and pedestrians could kill drivers with a careless turn of a wheel? Wouldn't dribers demand that peds take extra precautions that may not be optimal for them?

The bottom line is that anyone who spends a decent amount if time walking and biking the streets knows what a mental tax the stress of having high speed vehicles whipping around you creates. So, calming traffic greatly enhances the non-motorized travel experience and safety.

by Falls Church on Oct 14, 2012 12:01 am • link • report

I've paid 1000 bucks in speed camera tickets and tickets from officers.

It is not that hard to figure out what the speed limit is and where the speed cameras are and simply not speed past the threshold. I got a speed camera ticket last February for $100. That sucked. I haven't got one again, simply because I know better than to speed there. This isn't rocket science.

And, yes, they need to fix those speed limits on NY Ave, Porter, and Rock Creek Pkwy. Synchronizing the traffic lights on Georgia Avenue would help, too.

by Tyro on Oct 14, 2012 8:34 am • link • report

I feel like it's pretty easy to avoid paying speed camera fines. If you can't manage to follow the law, thank you for your donation to my city's treasury.

by Amber on Oct 14, 2012 9:17 am • link • report

The speed-camera proponents insist on using state statistics to justify their claim that speed is a factor in many fatal collisions. But the District of Columbia isn't a state, and doesn't have but a tiny amount of high-speed roads. It's a city, not a state, and any comparison to any state is misleading.

"In Maryland from 1998-2004 speeding was responsible for 20% of all crashes." Indeed, and in DC, in 2009, speed was the cause of 2.9% of all crashes. So can we stop using state data and assuming that they're meaningful for DC?

As for that 2.9%, I'd wager that most of those were reckless-driver crashes, not merely drivers going a bit faster than the limit. One of my constituents was killed by being broadsided by a car racing through a red light. The driver of said car was fleeing police pursuit after a robbery. Speed and red-light cameras were the last thing on that guy's mind.

I've asked for one example, just one, of a fatal collision that might have been prevented, or even mitigated, by speed cameras. I've yet to be shown one.

by Jack on Oct 14, 2012 10:20 am • link • report

The term "speed kills" is a misleading statement. The real danger here most often is differential speed and not absolute speed as all collisions involve two or more objects traveling at different speeds and/or directions. Thus, in the case of limited access highways such as 295, a situation where everyone is traveling 55mph is a safer scenario than if some vehicles are traveling 55mph and others traveling at 45mph. Couple that with people braking at known speed camera locations and obsessively looking at their speedometers instead of the road and we have the potential for a deadly combination of distracted driving and differential speed. While speed cameras and low speed limits may be making the roads more safe in residential areas, they may actually be making the roads less safe in the case of limited access highways.

by Scott on Oct 14, 2012 10:37 am • link • report

The term "speed kills" is a misleading statement. The real danger here most often is differential speed and not absolute speed as all collisions involve two or more objects traveling at different speeds and/or directions

Here are the facts on speed killing:

Relationship of Vehicle Speed to Odds of Pedestrian Death in Collision

Vehicle Speed Odds of Pedestrian Death
20mph 5%
30mph 45%
40mph 85%

http://humantransport.org/sidewalks/SpeedKills.htm

Yes, differential speed is what matters. You don't want a difference of more than 10mph between objects as noted by other commenters. Considering that peds walk at about 3-4mph, that implies a safe speed for cars of 13-14mph.

by Falls Church on Oct 14, 2012 10:58 am • link • report

But the District of Columbia isn't a state, and doesn't have but a tiny amount of high-speed roads. It's a city, not a state, and any comparison to any state is misleading.

When you're talking about car/pedestrian accidents, 25mph is a high speed road. Consider that more than half of all people killed in DC traffic accidents were pedestrians (20% in MD). It's reasonable to assume that if the cars in question didn't hit the pedestrians at such a great speed, the peds would still be alive.

Source:http://www.washingtonpost.com/local/trafficandcommuting/half-of-dc-traffic-fatalities-were-pedestrians/2012/08/06/107be118-dff8-11e1-a19c-fcfa365396c8_story.html

by Falls Church on Oct 14, 2012 11:06 am • link • report

"When you're talking about car/pedestrian accidents, 25mph is a high speed road."

Indeed, but what's that got to do with speed cameras? Are pedestrians popping up in front of cars moving at full speed? Most pedestrian collisions in DC occur downtown.

"Consider that more than half of all people killed in DC traffic accidents were pedestrians (20% in MD)."

As I've pointed out, that ratio is high in DC only because the number of automobile-occupant fatalities has decreased sharply. The number of pedestrian deaths remains unchanged, despite the proliferation of red-light and speed cameras. One might fairly conclude that the latter aren't doing pedestrians much good.

http://dcjack.org/images/NHTSA%20chart.jpg

"It's reasonable to assume that if the cars in question didn't hit the pedestrians at such a great speed, the peds would still be alive."

I don't think "great speed" is the problem downtown, where most pedestrian collisions occur. You might better worry about truck-frame-based SUVs, which are twice as lethal in pedestrian collisions as are sedan-type cars, due to their high front-end profile.

by Jack on Oct 14, 2012 11:37 am • link • report

OK, I agree about the area east of NY Ave seems under-rated. At the same time, there are studies showing that slowing the maximum speed actually improves flow by decreasing the chance of accidents, which REALLY slows traffic. I know that after being stuck in traffic on NY ave, I really want to let it rip.

by SJE on Oct 14, 2012 11:40 am • link • report

@Falls Church

"Yes, differential speed is what matters. You don't want a difference of more than 10mph between objects as noted by other commenters. Considering that peds walk at about 3-4mph, that implies a safe speed for cars of 13-14mph."

You completely dodged my point about differential speeds on limited access highways where pedestrian traffic is absent. On limited access highways, the relevant differential speeds are between two or more vehicles and not between vehicles and pedestrians. In fact, your statement that "you don't want a difference of more than 10mph between objects" actually supports my position against speed cameras coupled with speed limits that are significantly lower than the average flow of traffic on limited access highways. Both of these factors increase differential speeds on limited access highways and both you and I agree that differential speeds make the roads less safe, not more.

by Scott on Oct 14, 2012 12:18 pm • link • report

My own near misses with cars as a pedestrian come off as a stereotype (but one that's true!): suburbanites in SUVs yakking on the phone in tricky spots like traffic circles or other complex intersections. On a recent trip to WV, I saw people fitting the same profile weaving all over the place---one woman nearly collided with a semi. The problems with many of the arguments here is that they try to fit a single variable solution to something complicated. Speed cameras alone won't prevent stupid, dangerous driving.

The use of cameras raise questions as to calibration, system monitoring, etc. which mix civil liberties and simple mechanics. They obviously serve as revenue generators, esp. when placed on commuting routes. Despite being a non-car owner, I have no problem recognizing this. There are many people who need to get around in an efficient way in the District (and elsewhere): mostly trades people and those doing deliveries, and the regulation of traffic (as opposed to simply slowing it down) needs to consider their needs which affect the cost of doing business here and our ability to access goods and services. The big picture deserves some attention rather than this kind of single focus panacea.

by Rich on Oct 14, 2012 12:23 pm • link • report

@ Falls Church:Yes, differential speed is what matters.

Probably more correct than just speed, but if we get technical, then my gut feeling says that probably the relative speed difference is the most relevant parameter.

If you're walking 3mph, then a 10 or 15 mph differences is HUGE. However, on I-70 in Missouri, a 10-15 mph is the difference between people who stick to the speed limit and those who speed a little. Meh.

By the way, please realize that the speed difference doubles for oncoming traffic.

by Jasper on Oct 14, 2012 2:43 pm • link • report

Indeed, but what's that got to do with speed cameras? Are pedestrians popping up in front of cars moving at full speed? Most pedestrian collisions in DC occur downtown.

In most instances, cars are able to slow down some from full speed before hitting a ped. The lower their full speed, the easier it is to slow down to a speed that will result in less injury for the ped.

The number of pedestrian deaths remains unchanged, despite the proliferation of red-light and speed cameras. One might fairly conclude that the latter aren't doing pedestrians much good.

However, the number of ped trips has increased significantly. If you can hold the number of deaths constant as you increase the number of trips, that's an accomplishment.

I don't think "great speed" is the problem downtown, where most pedestrian collisions occur.

68% of ped fatalities in DC occur at night, particularly after 9pm. Downtown is empty at that time of night. So your assumption that most ped fatalities occur downtown is incorrect.

You completely dodged my point about differential speeds on limited access highways where pedestrian traffic is absent. 

I completely agree with you that cameras have no place anywhere where ped/bike safety is no concern For example, the cameras on DC's interstates are revenue generators which should be removed. Those cameras make it politically difficult to install cameras in places where they could improve ped/bike safety. They are the rotten apples that spoil the batch.

by Falls Church on Oct 14, 2012 4:20 pm • link • report

@ Falls Church: For example, the cameras on DC's interstates are revenue generators which should be removed.

Really? You're ok with someone blowing into DC on I-395 going 75 mph? You're ok with someone going 85 mph in I-295?

by Jasper on Oct 14, 2012 7:34 pm • link • report

Personally, I enjoy having to constantly defend the merits of speed cameras because the presence of a few in areas where they aren't as effective in one area or on a highway (where the speed limits are obviously to low even though there isn't any proof or justification for this).

In other news, there is a bus route that doesn't benefit me. Why do we have buses at all?

Also why do we have to ensure that all streets no matter the hierarchy must reflect "their natural speed" before we add cameras? I understand people feel like some speed limits are arbitrary but there is going to be a level of abritrariness at any level. So let's calm streets but don't use it as some sort of trump card when you speed and say "But the street made me do it!"

by drumz on Oct 14, 2012 8:20 pm • link • report

If the speed limits are to be so low at least post numerous signs, perhaps more numerous than usual. DC seems to have fewer than needed.

Drivers usually go with the flow of traffic and that flow is clearly above what the limits are in many places. Posting plenty of signs would achieve the goal of slowing traffic, although it would also lower revenue.

by Tom Coumaris on Oct 14, 2012 11:10 pm • link • report

@Jasper

Who the heck said anything about being OK with somebody going 85mph on 295 or 75mph on 395? How can you draw such conclusions from anything that has been written here? Anyone driving 85mph on 295 or 75mph on 395 would be driving significantly above the average flow of traffic and, thus increasing the speed differential on the highway. The same concept applies to vehicles traveling above the average flow of traffic is it applies to vehicles traveling below the average flow of traffic.

by Scott on Oct 14, 2012 11:29 pm • link • report

So let's calm streets but don't use it as some sort of trump card when you speed and say "But the street made me do it!"

Given the reality of democratic government, it makes perfect sense that speed limits should be aligned with public preferences and that people would petition their government for speed limits in line with their preferences.

DC's problem is that it really is a driving city: public transit is simply not capable of moving people within the city itself, so ultimately driving becomes necessary for many people. As long as that reality exists, the needs of drivers and the need to efficiently and effectively get from one end of the city to the other by car will be an important public priority.

by Tyro on Oct 14, 2012 11:30 pm • link • report

Indeed, and in DC, in 2009, speed was the cause of 2.9% of all crashes. So can we stop using state data and assuming that they're meaningful for DC?

@Jack: In the source I gave, DC had 44 traffic fatalities in 2007 and 8 were speeding related. That means 18% of fatalities were speeding related. That rate is certainly lower than the US average. I attribute the difference to DC's speed limits being generally in the 25-30 mph range, and its streetscape designs which encourage slower speeds.

I've asked for one example, just one, of a fatal collision that might have been prevented, or even mitigated, by speed cameras. I've yet to be shown one.

@Jack: Here is a pretty good metastudy of 28 traffic camera studies, all of which found reductions in the number of crashes:

http://gridchicago.com/wp-content/uploads/2012/04/Speed-cameras.pdf

and another metastudy of 13 studies:

http://trb.metapress.com/content/b5k4k42jxp7t265p/

Concerning urban streets, the National Academies study "Managing Speed" from way back in 1998 still has some good recommendations. Here are a couple of quotes:

"Basing the speed limit on a measure of unconstrained free-flowing travel speed is not appropriate for urban roads with a mix of road users and high traffic volumes and levels of roadside activity."

"Speed limits alone will not be effective in all situations. Keeping driving speeds at desired levels in urban areas poses a particular challenge. Traffic calming can be used judiciously on residential streets, but community as well as resident support is important for its success. Systemwide effects must also be considered so that the traffic and safety problems will not simply migrate to other streets. Road redesign has the potential to achieve greater consistency between desired and actual operating speeds."

http://www.trb.org/Main/Blurbs/152251.aspx

by Laurence Aurbach on Oct 15, 2012 12:26 am • link • report

Three points:
-- A need for better enforcement and more speed is an implicit failure of road and intersection design. Drivers should WANT to drive a safe speed, and that speed should be the speed limit. Having speed limits lower than the actual speed limit clearly suggests entrapment and undermines the legitimacy of the law, and/or that the road is badly designed for the prevailing conditions.

-- The 10 mph enforcement "cushion" in DC is high. In other states it is 5 mph -- for example in Pennsylvania they pull people over for going 62 mph on the Penna turnpike. The error on lidar is quite good: -2/+1 mph. So the cushion could certainly be reduced from to 5 mph over the posted limit.

-- What is dissatisfying about "slower is safer!" sort of arguments is there is no acknowledgement about the loss of mobility. Taken to the point of absurdity, I could argue that the speed limits should be lowered to 2 mph because (+ 10 mph enforcement cushion) a prevailing speed of 12 mph saves lives. Lowering speeds ALWAYS saves lives, but this also means it takes more time to get someplace. A balance must be struck between these conflicting considerations.

by goldfish on Oct 15, 2012 3:17 am • link • report

IF DC's speed enforcement program was about safety, "photo enforcement" wouldn't even be an option in locations where safety is in question because common sense tells anyone that a speed camera CANNOT stop a reckless or drunk driver from crashing and killing anyone.

A dangerous driver going 50 or 60 in a 25 zone won't be pulled over by a speed camera; he'll just keep tearing down the road, potentially into a fatal crash. A speed camera can't issue citations for reckless driving or DUIs; bad drivers don't get any points on their licenses for speed infractions caught on camera. Cameras are totally ineffective against stopping that type of driver or preventing the damage they can do.

And that type of driver is far more dangerous than the current target of speed cameras - some commuter trying to get to work.

by ceefer66 on Oct 15, 2012 7:32 am • link • report

Cameras can't enforce all laws so we shouldn't have any!

by Drumz on Oct 15, 2012 8:12 am • link • report

And how is DC a driving city when a significant population of adults don't even own cars? Not to mention the fact that making sure that people follow the speed limit (which is set by a standard, good or ill, and can become a voter issue if need be) mean that DC is no longer driver friendly?(whatever that means)

by Drumz on Oct 15, 2012 8:14 am • link • report

Actually, the whole problem with this article is the premise: zero traffic deaths.

That is an unachievable goal. Unless you remove all vehicles -- trucks, cars, even bikes -- from the streets. And I'm sure then you've have a few deaths from heart attacks or heat stroke.

by charlie on Oct 15, 2012 9:09 am • link • report

@charlie: maybe zero traffic deaths can be achieved if all vehicles were self-driving. (Discuss...)

by goldfish on Oct 15, 2012 9:14 am • link • report

Self driving cars would be nice and it'd be wonderful if they eventually render cameras moot. However since we are a good ways from self driving cars being ubiquitous I view them the same as the "the street is designed for that speed!" Argument which is deflection off of what's actually happening.

by Drumz on Oct 15, 2012 9:17 am • link • report

Pedestrians > Bicycles > Public Transportation > Private Transportation.

If all urban transportation policy follows the above precedence for policy decisions, pedestrians would be safer, the presence of bicyclists would be more prevalent, buses and street cars would have the ROW, and private cars, due to the increase of multi-modal transportation options for everyone else (and assuming the price of keeping a private vehicle in the city is at market value), would see significant decrease in congestion, allowing drivers to get to their final destination at reasonable speeds, without feeling subconsciously pressured to speed due to poor road design.

As an occasional driver who pays for his spot in a private garage, I know I’d rather coast at 20 MPH than stop and go at 30MPH. It’s amazing (and I’m sure those who disassociate from regular driving would agree) how one’s stress level goes up when a driver is delayed for even just a few seconds due to somebody else. I always have to remind myself to think that this is much faster and much more comfortable than sitting on a bus right now, even if it took me an extra 10 seconds than planned.

by cmc on Oct 15, 2012 9:30 am • link • report

@Drumz

"Cameras can't enforce all laws so we shouldn't have any!"
----

Have you ever heard of a live police officer on traffic patrol duty? That might appear somewhat archaic [deleted for violating the comment policy] but they are quite prevalent.

by ceefer66 on Oct 15, 2012 9:34 am • link • report

Fun fact, some people are fine with camera enforcement AND police officer's enforcing traffic laws as needed.

by drumz on Oct 15, 2012 9:53 am • link • report

You're ok with someone blowing into DC on I-395 going 75 mph? You're ok with someone going 85 mph in I-295?

If you set the speed limit on those interstates at 55mph, with cameras designed to catch people going over 62mph, I'd be perfectly fine with it. That would be reasonable enforcement of a reasonable speed limit.

by Falls Church on Oct 15, 2012 10:47 am • link • report

me: I don't think "great speed" is the problem downtown, where most pedestrian collisions occur.

Falls Church: 68% of ped fatalities in DC occur at night, particularly after 9pm. Downtown is empty at that time of night. So your assumption that most ped fatalities occur downtown is incorrect.

Um, can we refrain from confusing "collisions" with "fatalities"?

BTW, evidently you're a suburbanite, and you have no idea of the street population of downtown DC at night. In a word: thriving.

by Jack on Oct 15, 2012 11:29 am • link • report

As for where pedestrian collisions occur (collisions, I said, not "fatalities") -- here are 2009 data:
http://dcjack.org/images/ped%20collision.jpg

by Jack on Oct 15, 2012 11:47 am • link • report

Anyone who has: walked to a bus stop on Porter St. near the intersection with Williamsburg Ln, including crossing Porter to get to the right side of the road; ridden a bike up or down Porter to/from Conn. Ave/the Rock Creek trail/Irving St., knows the speed camera on Porter is well placed and needed.

See comments by @FallsChurch, @Jasper, @Drumz, @cmc, etc above about non-motorized users, auto speed, collisions and safety.

by Tina on Oct 15, 2012 11:57 am • link • report

David, I'm glad you at least acknowledge the artifically low limit in many places. Sadly, these areas also seem to be the most heavily enforced. I'm perfectly comfortable observing the posted speed limit, but it's not intuitive, often not clearly marked, and automated enforcement allows presents little real cost to the city, yet with significant cost to drivers penalized for extremely minor violations. Like street parking enforcment, it's become another cash cow. The fines are disproportionate to the offense and justified in the so called interest of public safety, when in fact it's largely just another lucrative revenue stream for DC.

I received a photo enforced $175 ticket approaching East Cap Whitney Young bridge adjacent to RFK stadium, which transitions to 295. The recorded speed? 36 miles/hr in an area that isposted 25 mph and artifically low (who knew? -- I've driven it for the past 15 years). It's a cruel joke. However much I don't like it I can still afford it, but I feel for people for whom that fine would impose a real hardship.

by anon_se on Oct 15, 2012 12:05 pm • link • report

@Tina
Anyone... knows the speed camera on Porter is well placed and needed.

So needed that they removed it?
http://dcist.com/2012/09/porter_street_speed_camera.php

It will be interesting to see if speeds go up now.

by MLD on Oct 15, 2012 12:08 pm • link • report

BTW, evidently you're a suburbanite, and you have no idea of the street population of downtown DC at night. In a word: thriving.

This suburbanite happens to be plenty familiar with the street population of downtown DC at night. With the exception of Gallery Place, what area of downtown would you describe as having a thriving nightlife? Downtown is mainly comprised of offices, retail, and restaurants that cater to the lunchtime & happy hour crowd.

As someone who writes about Columbia Heights & Mt. Pleasant, are you familiar with downtown DC? Here is a primer for you from wikipedia:

By the 1990s and continuing into the 2010s, the core of the downtown district was almost exclusively commercial, and its primary commercial use was as office buildings...However, even as late as 2010, most of the core area tended to be empty of pedestrian foot traffic at night, except for streets immediately around theaters and restaurants.[5][10] Downtown D.C. has been adding residents, however, and pedestrian traffic at night is increasing. In 1990, the area had about 4,000 residents, but this had increased to 8,449 by 2010.[11] Such increases appear small, but are more significant than they seem because the city's height restrictions limit population density.[4] The completion of the $950 million CityCenterDC project in late 2013 is estimated to add another 1,000 or more residents.[11] One exception to the low nighttime foot traffic is Gallery Place.

http://en.wikipedia.org/wiki/Downtown_%28Washington,_D.C.%29

Um, can we refrain from confusing "collisions" with "fatalities"?

The only data I had was for fatalities. It's reasonable to assume fatalities and collisions are highly correlated but if you have data that's specific to collisions, please share.

by Falls Church on Oct 15, 2012 12:11 pm • link • report

@Jack

Just saw your link with collision data. I wouldn't call it conclusive but the collision rate downtown does seem higher than the fatality rate would suggest. That probably means those are lower impact collisions that don't create fatalities. So, maybe speed cameras aren't needed downtown because traffic conditions make it difficult to drive faster than the speed limit or at a speed that would result in fatalities. That's probably why there are few (if any) cameras downtown.

by Falls Church on Oct 15, 2012 12:19 pm • link • report

@Jack

Just noticed that your data is only for pedestrian collisions at intersections. Only 21% of ped fatalities occur at intersections. So, if you had data for all collisions (not just ones at intersections), you might see a lesser share downtown.

by Falls Church on Oct 15, 2012 12:24 pm • link • report

@MLD -yeah it was removed -because it was determined that it had accomplished its mission of getting drivers to routinely drive slower. For many years there was a cop parked on Porter near Williamsburg Ln with a radar gun between 4 and 7pm nearly every week day. Maybe that cop will get his/her job back with the removal of the camera...

Yes, speed control at that spot is important.

by Tina on Oct 15, 2012 12:31 pm • link • report

OMG:

How many posts about how "I am impeded"?
How many posts about the right speed?

crybaby
n. pl. cry·ba·bies
A person who cries or complains frequently with little cause.

by gunnysack on Oct 15, 2012 2:45 pm • link • report

Last week, I was traveling on New York Ave inbound at Blandensburg Rd, I am sitting at the light and notice a car attempting to make a left turn from Bladensburg to New York Ave heading East when the no left turn light is on.

Multiple cars blew their horn at the vehicle and the driver did not care and made the turn anyway when possible. A cop was at the gas station nearby and jumped out between the intersection after the driver making the illegal left turn. No camera would have caught that nor does it detect other violations. I can easily put my car on both lanes and still follow the speed limit but the camera wouldn't care.

by Clear Ops on Oct 17, 2012 11:54 pm • link • report

hahaha, more scofflaw drivers complaining that they have a god-given right to drive as fast as they want and screw anyone they run over. as long as this continues I don't want to hear a thing about "scofflaw cyclists".

it's also hilarious how the non-residents supposedly want dc to pay for more traffic cops. we all know that if there were more traffic cops they'd all be complaining that dc was spending money on traffic enforcement instead of "safety". the only reason they want cops is because they know they can usually get away with breaking the law because the cops aren't as reliable as the cameras.

by Mike on Oct 18, 2012 7:34 am • link • report