From Potholes to Political Pavement: Road Repair in Pittsburgh [Urbanism]

Destroyer of axles, wrecker of undercarriages, bane of wheel alignment, tireless foe of tire tread -- ladies and gentlemen, I present The Pothole.

This bad mother lived over on Negley Ave, just north of Fifth Ave. Negley is a main artery from Squirrel Hill down into Shadyside, Bloomfield, Friendship, and Garfield. From Wilkins one can take it down one of the steeper grades in the city, across Fifth, and right into this pothole, which sits on the far right side of the northbound lane.

Busses (especially the 71s and the 500) use Negley to get to Center, and I've seen a couple of them enlarge this sucker as the pass, ripping little pieces of the roadway off and out.

It took the city six days to fix this bad boy, from my notification to them on the 8th, to further notifications on the 11th and 12th, to its ultimate repair on the 13th.

It's clear what potholes are -- big holes in the road where the road surface seems to have collapsed or been removed, leaving bare earth (or sometimes gravel) underneath.

The word Pothole (and the synonyms Kettle and Kettle-hole) was first used not by angered motorists, but by naturalists and geologists, to describe pot or kettle-shaped holes, usually quite large, formed by the gradual spiraling erosion of those rocks by nearby water sources (usually rivers or oceans).

Essentially, natural potholes are formed when pebbles settle into a depression in a rock, and then are washed repeatedly across the rock-face by flowing water. As the pebbles spin round and round the depression, they slowly carve it out, forming a hole many, many times larger than the pebbles themselves.

Road-potholes are great analogs to natural ones, but require a little more explanation.

The smooth, even road-surfaces we are used to are a pretty recent innovation. They are made of asphalt or concrete, both words that describe pliable mixtures of mineral aggregates (gravel or rock or sand) and a binding agent that glues this slurry together. One heats the mixture up, pours it onto the road that needs surfacing, and compresses it to cool, whereupon it hardens into a smooth, glossy driving surface.

It is, of course, not that easy.

First, one needs an appropriate road-bed to put this surface on -- hardpacked stones and gravel that won't erode away if the ground around it does. If the underlying roadbed is too weak, or starts eroding, then the cemented surface above it will start to stress, crack, and break.

Second, really strong asphalts are both expensive and temperamental. Both the binding agent and the mineral aggregate in any given mix have a large scale of options, and the best-of-the-best can cost probably two orders of magnitude (100x) more than the cheap stuff. Additionally, the strongest cements can only be laid down in the summer months, as the longer they take to cool, the stronger they are, and the less likely they are to crack. Even worse, if one paves in winter, the mix cools before it can be properly compressed and shaped.

Most municipalities opt for the (pardon the pun) middle-of-the-road options when it comes to construction and paving -- not God's Own Paving Slurry, but not Pebbles-N-Spit either.

The More You Know:

There are actually two famous Scottish men named M(a)cAdam in history. John Loudon McAdam, no 'a' in Mc, invented the modern way of paving roads (mineral aggregate + binding agent), while John Macadam, 'a' in the Mac, is known as the botanist who discovered Macadamia nuts!

The middle-of-the-road stuff is, of course, susceptible to nature's wrath, especially the wrath of water. General erosion, combined with the heat-and-thaw cycles common to Northeastern winter, do much to soften roadbeds. Hundreds and thousands of cars (which it should be noted are thousands-of-pounds machines that rest on just four contact-points) traveling over the road-surface every day, pounding snow and water and dirt down into it, does the rest. Stress cracks form, fill with water, freeze and expand, over and over again until the tires of the cars can get a bit of a foothold on the crack-lip and start tearing out the very surface they rely on. A pothole forms, and as cars pick up the gravel in the center of the hole and push it towards the edges, or slam their tires into the new couple-of-inches-deep sides of the hole, the kettles get bigger, and bigger, and bigger.

Just like their natural counterparts, potholes that also hold water grow the fastest, as the water actually washes all the abrasive gravel back into the center of the hole, making the hollowing process even more efficient.

Pittsburgh's roads have even more complications than the average city. We are an old city, without much of a grid, built on many, many hills, and many of our streets are paved-over cobblestones. Additionally, we have a couple of the steepest streets in the hemisphere. Also, our public transport busses and delivery trucks can actually pull roadways apart when they stop repeatedly at the same places.

Here is one such stress-crack, at the bottom of Murray Avenue in Squirrel Hill.

All of this is to say: Pittsburgh has potholes, and new ones form every winter, quite reliably.

Bram Reichbaum wrote an excellent expose about Pittsburgh's paving and pothole filling habits over at his news-blog-paper The Pittsburgh Comet. Essential conclusions: the city has no money, and prefers to ignore the little problem --- sealing cracks, reinforcing obviously-deteriorating roadways, filling sprawls and holes and joints, and noting frequency of repair, all of which costs not-small amounts to fix -- and let them snowball into larger problems (potholes or even Capital Investment-level repairs), which cost much, much more to fix. This would be fine, except that by the city's own admission (pdf link to their 2009 Street Maintenance Audit), ignoring preventative maintenance and only fixing problems when they become public, political problems, is wildly more expensive than just fixing things right, once, when they are small.

It gets so much better, though.

As mentioned above, in winter it is too cold to effectively use hot asphalt to fill potholes. Instead, the city uses what it calls cold-fill, which should be called coal fill. Cold-fill is, no joke, bituminous coal mixed with tar. Coal. Coal, heat-your-house-with-it coal, is used to fill thirty- to thirty-five thousand potholes every Pittsburgh winter. It is grossly ineffective, and many of those 35,000 potholes are therefore repeat offenders.

As they say in the movies though, follow the money. Cold (Coal) Fill costs $69 a ton. Rapid Set, an asphalt mix used by Columbus and Cleveland to great effect, costs $12 a bucket, or (assuming a five gallon bucket weighs seventy-five pounds, which is a low estimate based on this datasheet) $320 a ton, an almost fivefold increase.

Even better is the asphalt mix that the city has started to use to repave streets. Called Superpave, it has been adopted by the state as the go-to mix for repaving streets and highways. Unfortunately, though it was touted as being able to last ten or fifteen years, the parts of the PA Turnpike that use it have cracked in just five.

Besides logistics and funding, potholes (and paving generally) have turned into quite the political issue.

In October 2006, an official "Mayor Luke Ravenstahl's Response Line", 311, was set up. One of its features is the ability to call in and report potholes.

On July 1, 2008, there was criticism from Councilman Bruce Kraus concerning the way in which street paving around the city might be politicized: various city employees have conflicts of interest as they both work for the paving department and sit on neighborhood specific councils. Mayor Ravenstahl announced plans to contract with infrastructure-data firm CarteGraph to track repairs apolitically, plans which don't seem to have publicly materialized.

A report released by the city in early 2009 showed that the city was neither reaching its own goals as to how much it paved, plowed, and de-potholed, nor was it following its own best-practices guidelines for any of those activities.

March 11, 2009, the mayor launched pittsburghpothole.com, a redirect to a pothole reporting form on the mayor's website. The form has just two large fields for entering data about the pothole, and ten fields, all of them marked "Optional", for personal data about the pothole-reporter. It doesn't seem to do more than auto-fire an email towards the mayor's office. It does not send the reporter a confirmation email, or even a way to track the request entered. It is a one way street, almost as bad as tossing requests over a wall.

That same day, City Councilman Bill Peduto called for an approximately $3M system-and-staff that would not only let citizens report potholes and other infrastructure problems, but track their repair for the city. This plan, like the Mayor's hundredth-of-the-price one from a year previous, has not seen further daylight.

It was also reported that the Stimulus Package was sending $4.5M Pittsburgh's way for Community Development. Saith the Mayor, "When specific program guidelines become available, I will be working with members of City Council to help formulate an aggressive paving program." As far as this journalist knows, no such program has been widely announced.

August 2009 the city launched an iPhone application, iBurgh, which let users upload geo-tagged photos and descriptions straight to the city. The app has gotten over 8000 downloads, but it is unclear how many actual issues have been reported via it (and how many of those actually got addressed).

Just last month, the Post-Gazette had a great writeup of what has and hasn't been working (and what Non-Emergency Responses the city does and does not respond to), which included a link to PittMAPS, another wing of the mayor's website.

PittMAPS reports back some amount of data about infrastructure complaints and repairs, though not enough to actually corollate how many pothole reports were responded to, what percentage of pothole fixes were based on reports, etc, just totals for "Potholes Repaired" by quarter, and "Potholes reported" by quarter. Unfortunately, it does so by hosting a series of information-lite pdfs and impossible-to-read jpgs, rather than more easily accessible data (html?). It was reminiscent of the Port Authority website, come to think of it.

I guess that makes sense, considering parts of the mayor's recent inaugural speech (emphasis mine):

"[The city's job] isn't just about paving streets and keeping crime at bay. It's about championing and marketing our neighborhoods to new residents and businesses."

You're right, Mr. Mayor. If there's anything this city isn't about, it's paving streets.