Steve Mouzon is a Strong Towns member and author of The Original Green book as well as the Original Green blog. Today's article is republished from Steve's blog with permission.


Two groups injured and killed most often are the young (because they’re small) and the elderly (because they’re fragile).  All images in this article are from Celebration, Florida where scenes like this could soon look very different if the deputy fire chief and traffic engineer get their way

Two groups injured and killed most often are the young (because they’re small) and the elderly (because they’re fragile).  All images in this article are from Celebration, Florida where scenes like this could soon look very different if the deputy fire chief and traffic engineer get their way

Of all the urbanism specialists with tunnel vision, fire chiefs, fire marshals, and traffic engineers are probably the most dangerous. And by “dangerous,” I don’t just mean that they’re a threat to good urbanism; they also get people killed, which is exactly the opposite of what they are commissioned to do. A classic example of their silo thinking is playing out right now in Celebration, Florida, where the proposed measures of eliminating on-street parking spaces and eliminating street trees will almost certainly leave Celebration a less safe place than it is today.

More driving = more crashes and more deaths and injuries.

Let’s look at things from both a common-sense perspective and a data-driven perspective. Getting rid of street trees does some really bad things for safety: First, it eliminates the first line of defense for those who are walking or biking on the sidewalk (when the streets are too dangerous for biking). A car crashing into a tree at 35 miles per hour will deploy the airbags, but the driver and passengers will likely walk away with little more than bruises. But a car traveling 35 miles per hour that crashes into someone who is biking or walking will likely kill them. Higher speed = more deaths and injuries.

People adjust their driving according to the conditions around them. On a tree-lined street, people tend to drive slower because they don’t want to hit a tree if they lose control of their car and run off the road. Lower speed = fewer deaths and injuries.

There’s another problem with removing street trees: They make a huge difference between walking and driving in places that are hot in the summer (like Orlando). A canopy of street trees not only eliminates the strong radiant heat of the sun with its shade, but also cools you even further with the trees’ respiration, which has a similar effect to a cool mist. With a cooling canopy of street trees, most people walk well up into the 90s. With a hot sun beaming down, those same people rarely walk, even in the low 80s.

But there’s yet another problem: Humans get conditioned to everyday behavior, so when treeless streets condition them not to walk on moderately hot days, driving becomes their norm. And when you increase driving, you increase crashes and traffic deaths. There are even more reasons not to eliminate street trees, but that’s another story for another day, because it doesn’t involve safety. 

On-street parking is equally essential to safety, and for even more reasons. As a matter of fact, on-street parking and street trees top the list of things cities should increase on streets if they’re interested in increasing the safety of their citizens. To be clear, the prime benefit of these two elements is getting people out of their cars because they prefer to walk to their daily needs. The two extremes are places where everyone drives (suburbia) and places where everyone walks (European towns and villages). Where everyone drives, there are huge numbers of deaths per year because of crashes. In most places where everyone walks, nobody has ever died due to running into someone else.

Imagine this scene with all the trees cut down and cars driving a lot faster.

Imagine this scene with all the trees cut down and cars driving a lot faster.

Walking to daily needs is therefore the safe ideal; it’s stunning that the deputy fire chief and traffic engineer seeking to ruin Celebration don’t realize this. Here are the minutes of a recent meeting that illustrate their blindness to these facts. Note also how the officials talk out of both sides of their mouths. At one point, it sounds like they only want to remove one parking space closest to the end of each block, but when pushed, there are actually several entire streets where they want to remove all on-street parking.

A shady Celebration sidewalk

A shady Celebration sidewalk

This kind of double-speak is often found at the Department of Transportation. When the Flamingo Park Neighborhood Association was fighting the Florida DOT over the safety and character of Alton Road, the DOT finally agreed to put a landscaped median in the middle of Alton. But just before construction began, they released their final drawings showing that the “median” was actually two half-block-long turn lanes with one ridiculous palm tree in the middle of the block, where the turn lanes switched from one side to the other! In good DOT fashion, it was a classic case of “too soon to know” switching instantly to “too late to change.” I’m an optimist on most things, but I fear this tactic may be used to wreck Celebration.

On-street parking does several good things, and its alternative (on-site parking lots) does nothing good. Google “sea of parking.” Are any of the hits positive? Of course not; a sea of parking is dreadful on all counts. Beyond the obvious ugliness, they heat the microclimate by absorbing solar radiation and heating the air above them. Heating the microclimate makes walking uncomfortable and so people drive, even if the parking lot is out of sight. More driving = more crashes and more deaths and injuries.

“But what about on-street parking,” you might ask? “That’s paving, too.” Yes, it is, but it’s a lot less paving. Parking lots need travel lanes between the parking spaces. A 65’ wide perpendicular parking bay has two 18’ parking spaces and a 29’ travel lane. On-street parking needs no extra travel lane because the street itself is the travel lane. So off-street parking requires almost twice as much asphalt and destroys almost twice as much green space as on-street parking, heating the microclimate almost twice as much, discouraging walking and encouraging driving. More driving = more crashes and more deaths and injuries.

If parking lots were all put in the middle of the block, it would do less damage to the urbanism because it wouldn’t be visible from the street. Unfortunately, parking is far too often put in front of the building, just behind the sidewalk. If the street is heavily traveled, this creates the dreadful W0 Walk Appeal condition where people simply do not walk unless their car breaks down. Parking lots in front kill walking and increase driving. More driving = more crashes and more deaths and injuries.

Less driving = fewer deaths by automobile

Celebration sidewalk cafe protected by street trees

Celebration sidewalk cafe protected by street trees

On-street parking makes sidewalk cafes possible. It would be insane to have lunch sitting at a table where cars were zipping by at an almost-certain-death 35 miles per hour just a foot from your elbow. But with cars parked alongside the street, moving traffic is much less of a threat. Sidewalk cafes are both the highest indicator and the highest single stimulus of Walk Appeal, which is the best indicator of places where people walk more and drive less. To make a place safe, we need more of them. I haven’t done the research yet (that’s for a later article), but there’s a strong likelihood that places with many sidewalk cafes have fewer deaths by automobile per capita than those with none. Less driving = fewer deaths by automobile.

Without street trees, asphalt on the street on the left would be soaking up heat all day long, and therefore heating up everything around it.

Without street trees, asphalt on the street on the left would be soaking up heat all day long, and therefore heating up everything around it.

Walk Appeal is the strongest indicator of the likelihood of success of neighborhood businesses in walkable places. When businesses succeed in walkable places, more neighbors patronize them on foot and people drive less. Less driving = fewer deaths by automobile.

Similar to street trees but even more powerful, on-street parking (especially diagonal parking) reduces driving speed. The possibility of a parallel-parked car opening a door in front of you subconsciously slows you down; the possibility of a diagonally-parked car backing out in front of you does so even more effectively because that would be a worse crash than just knocking someone’s doors off. If a car strikes you traveling 20 miles per hour, you’ll likely suffer some bumps and bruises and maybe a broken bone or two; if a car strikes you traveling 40 miles per hour, I hope you have your things in order, because your family and friends will be burying or cremating you in a few days. The US DOT is the source of this information (scroll down to the Vehicle Impact Speed vs. Pedestrian Injury chart). Lower speed = fewer deaths and injuries.

It is insane that most traffic engineers don’t understand this! And their prejudice against safer design is cooked right into their standards: The AASHTO Geometric Design of Highways and Streets (the "Green Book,” which is the bible of traffic engineering), uses the Level of Service (LOS) system where streets are rated from A to F with A being best and F being worst, like grades in school.

Here’s the problem: LOS A is the free flow of traffic at the highest speeds (most deadly), while LOS F is a slow-moving traffic jam (safest). Speed kills… especially if you’re walking or biking. Higher speed is OK if you’re driving on an expressway through the countryside, but it’s decidedly not OK if you’re driving in a city or town.

To be blunt, the Green Book standards have probably killed hundreds of thousands of people in towns and cities. It’s deadly. Put a less dramatic way, the Green Book is great for highways in the country, but not for in-town streets. For that, you need Designing Walkable Urban Thoroughfares, a design manual jointly created by the Institute of Transportation Engineers (ITE) and the Congress for the New Urbanism (CNU). Sadly, many traffic engineers have apparently never heard of it, even though it reduces deaths and injuries in town, while the Green Book increases deaths and injuries in town by speeding up traffic. Higher speed = more deaths and injuries.

The deputy fire chief never actually said “cut the trees down.” He just said to remove them. But there’s no way you could move trees like these with any chance of them surviving.

The deputy fire chief never actually said “cut the trees down.” He just said to remove them. But there’s no way you could move trees like these with any chance of them surviving.

This brings up another problem: Eliminating on-street parking makes wider travel lanes. Of all the factors affecting travel speed, there is none more reliably calibrated than lane width. People behave differently in different settings. 9-foot travel lanes induce all but the idiots to drive no more than about 20 miles per hour. And it’s important to note that you can never design for the idiots, because there’s no way to predict what someone will do when they’re in an irrational state of mind. On 10-foot travel lanes, people tend to drive 20-30 miles per hour. 11-foot travel lanes should only be used on the highest-speed thoroughfares in town, where there is good protection (like high levels of on-street parking) for people walking. 12-foot travel lanes are Interstate lanes, and we all know how fast people drive on the Interstate. In town, 12-foot travel lanes should be called “death lanes.” Higher speed = more deaths and injuries.

The post office is one of many walkable destinations at Celebration. If walkability is damaged and more people drive, there’s probably not enough parking for them all.

The post office is one of many walkable destinations at Celebration. If walkability is damaged and more people drive, there’s probably not enough parking for them all.

A Look at the Numbers

Now, let’s look at some numbers.This is just the first in a data-driven series of articles. It looks broadly at nationwide numbers for general trends. Later, we’ll compare urban form: cities with tight-knit traditional urbanism versus cities built mostly of sprawl. From a fire perspective, one would think that the United States, built mostly of modern buildings on broad streets where large fire trucks can turn easily and where most buildings are built to modern fire codes, would perform far better than European countries, which are burdened with medieval urbanism, with narrow, cranky streets and small-pipe water. Here are the recent facts, all from 2007 (the last year for which I was able to get data for all these nations):

Fire deaths per million citizens:

  • USA: 12.4
  • France: 9.8
  • UK: 7.6
  • Spain: 5.2
  • Italy: 4.2

So US fire deaths are over 20% higher than the highest of the Western European countries selected and almost triple the deaths in Italy. I wasn’t cherry-picking; I chose the most populous countries in Europe nearest the US. Germany, for example, is substantially lower than Italy.

So the wealthiest country in the sample with the most modern buildings performed worst on fire deaths? Meanwhile, the other countries have buildings hundreds of years older, serviced by cobbled-together electricity and built on streets so narrow that many of them would be considered alleys in the US performed substantially better? How can this be? I’ll post later on the details of fire risk and urban form, but unless the Europeans are fantastically smarter than Americans and have much better reaction time, how else do you explain this huge discrepancy other than as a product of urban form? I suspect the primary cause of this difference that is costing over a thousand American lives per year is the difference in urban form.

It only makes sense that places requiring four times as many miles of streets per person (or more) would be harder to protect, even if the streets are wider and allow faster fire truck travel. If that’s the case, fire departments should be celebrating places with traditional urbanism like Celebration, and bending over backwards to support that urban form (including buying smaller fire trucks) because it makes them look better by being substantially safer. Instead, they’re punishing traditional urbanism and trying to damage it enough to bring it back to the unsafe standards of American sprawl.

It gets worse. Let’s look at those same five nations through the lens of death by automobile. If traffic engineers touting Level of Service standards were to be believed, the US should be the safest nation because more of our thoroughfares have been built to these modern standards. Meanwhile, Europe with its narrow, cranky streets should be really unsafe. Here are the facts, all from 2014 or 2015:

Deaths by automobile per million citizens:

  • USA: 119.7
  • Italy: 55
  • France: 52
  • Spain: 36
  • United Kingdom: 28

So the US, purportedly the safest nation according to accepted standards, is actually the worst in this sample, and by a large margin! The most unsafe nation in the sample other than the US is Italy, where it’s standard practice to pass a car on a highway approaching a hilltop beyond which you cannot see. And Italy is more than twice as safe as the US.

The safest country in the sample is the UK, which is more than four times as safe! If you average the non-US nations (42.75 deaths/million) and take the difference between that and the US multiplied by our population, then the logical conclusion is that our traffic engineering standards are killing about 23,000 people per year in the US!  As with fire standards, traffic engineers should be embracing traditional urbanism with open arms because it saves so many lives per year!

Every comfortable destination that becomes uncomfortable by cutting the trees down becomes one more reason not to get out and walk. Things like this park bench help build a stronger culture of walking in the community.

Every comfortable destination that becomes uncomfortable by cutting the trees down becomes one more reason not to get out and walk. Things like this park bench help build a stronger culture of walking in the community.

On the divide between traffic safety and fire safety, consider this: if you only count deaths by automobile of people walking and people cycling, that’s 19.4 per million in the US, which is almost 50% more than the egregious 12.4 per million deaths by fire in the US each year. To be really blunt, if every fire department in the US closed up shop and dedicated themselves to reducing deaths of people walking and biking to zero, 2,100 lives would be saved in the US every year. Over my lifetime of 57 years, 119,700 people we’ve buried or cremated would have lived instead, with not a single fire station open in the US. To be clear, I’m not advocating for that. What I am advocating is for fire chiefs and fire marshals to open their eyes and realize that when they do something in the interest of fire safety that damages walking and biking safety, they’re likely killing people!

Look, I understand that neither the deputy fire chief nor traffic engineer overseeing Celebration are evil people, intent on killing their neighbors. And I hope both of them are reading this. It’s likely that you guys got into your lines of work at least in part because you’re interested in helping people, and making them safer. But the standards of your specialties, because they focus so tightly on just a few specialized metrics like LOS are actually killing and maiming people, destroying families, and causing uncountable grief.

Your ideals are not wrong; your ideals are good. It’s your standards that are egregiously wrong, and causing much suffering. Do the right thing, and reconsider your standards. Let Celebration live, and may each of you stand as change-makers against unsafe regulations. Make places safer in real life, not in your tiny silos. The time is now.

(All photos from Steve Mouzon)


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