Monday, May 6, 2013

Civil Engineering: Traffic Problems in History

All roads lead to Rome . . .

 The Romans built a huge network of roads. They were primarily for military use, but also used for trade. In all, the Romans built over 50,000 miles of hard-surfaced roadway.

Before the roads were paved, the weather could slow down any kind of travel. Rain could wash away sections of road, flood areas, or turn highways into mud bogs after many feet trampled the soggy path.

In those days, you had to walk most places – imagine getting your best pair of Corinthian leather Birkenstocks stuck in a mud hole halfway from home!

"Where we're going, we don't need roads . . ."

In Italy, the engineers developed a form of concrete, made from volcanic ash and lime. They used this to build roads that were strong, straight, and cambered, to allow the rain to run off.

In Pompeii, the roads had other “modern” designs built in. They had crosswalks that were raised, so pedestrians could stay out of the mud. They also used white stones as reflectors, placed at regular intervals down the center of the road. These were bright enough to catch the light from the carriages.

That's a raised crosswalk, so pedestrians didn't have to walk in the dirty streets.
The wagon and chariot wheels were standard widths, so they could pass between the gaps in the stone.

A cross section of Roman street design, from:  A Dictionary of Greek and Roman Antiquities. London: J. Murray.

The general appearance of such a metalled road and footway is shown in an existing street of Pompeii.
(A). Native earth, levelled and, if necessary, rammed tight.
(B). Statumen: stones of a size to fill the hand.
(C). Audits: rubble or concrete of broken stones and lime.
(D). Nucleus: kernel or bedding of fine cement made of pounded potshards and lime.
(E). Dorsum or agger viae: the elliptical surface or crown of the road (media stratae eminentia) made of polygonal blocks of silex (basaltic lava) or rectangular blocks of saxum qitadratum (travertine, peperino, or other stone of the country). The upper surface was designed to cast off rain or water like the shell of a tortoise. The lower surfaces of the separate stones, here shown as flat, were sometimes cut to a point or edge in order to grasp the nucleus, or next layer, more firmly.
(F). Crepido, margo or semita: raised footway, or sidewalk, on each side of the via.
(G). Umbones or edge-stones.

Today most of the top layer of concrete has eroded, leaving the bumpy looking pavers on top, but at the time, these roads were smooth and fast.

Wednesday, April 24, 2013

Traffic Engineering: Saving the world one turn lane at a time.
Hardey Engineering and Assoc.

“You hit the brakes for a second, just tap them on the freeway, you can literally track the ripple effect of that action across a two-hundred-mile stretch of road, because traffic has a memory. It’s amazing. It’s like a living organism.” - Ethan Hunt (Tom Cruise), in his cover job as a traffic engineer in Mission: Impossible III.

I had to laugh as I heard this line in the movie. So many times while on a traffic count I had let my imagination run away with me. Instead of sitting in my truck for a 4 hours on a  grueling count of a suburban intersection, I was on stakeout. The placard in the window stating "Traffic Count in Progress" and the phone number of my employer, Hardey Engineering, were fake, a cover to distract passers-by.

It had to be more interesting that punching buttons on a glorified calculator, recording a sampling of left turns.

While watching "The Bourne Legacy" I had another flashback: sitting in front of two TV monitors with a cold pizza, watching a pre-recorded pair of intersections, tracking which cars passed through both, running the tapes back and forth.  In the movie, there were some grunt investigators doing the same thing to the traffic cameras, searching for the suspect's car.

Traffic Engineering: it's the perfect cover!

That's a Radar-gun.
Very few people actually know what it is.

Traffic Engineering is a unique blend of pairing the applied science of Engineering to the human decision-making process.  Not only do we predict present and future behavior, then we apply that flow to the roads and streets, to head off future problems.

Like water systems, traffic systems can only handle so many cars, and when that hits the maximum capacity, we get gridlock, accidents, and road rage.

Our job is to determine how much the system can handle, and how to improve the capacity. One of the tools we use is a traffic modeling simulator.

Like SimCity Traffic, but more math, and lamer graphics. 

Are you building a new subdivision? Do you need approval? We can tell you how many vehicle trips you'll generate,  how to make sure the neighborhood stays safe, and how to keep the neighbors happy.

Are you investing in a commercial shopping center? We can help you get your customers in and out of the building efficiently.  

Are you planning a Zone Change? Traffic Impact Studies help things so much smoother with the planning departments.

Do you need to save the world from the latest cyber-attack? Don't worry about it. We're already on the job.

Friday, April 12, 2013

Civil Engineering: Traffic Calming

What is a Woonerf?

In the U.S. they are sometimes called "Complete Streets."

They are areas that is shared by vehicles, cyclists, and pedestrians. The word for "Woonerf" (Pronounced "Vu-nerf") is loosely translated "Living Street."

The idea is to create a space where drivers feel more cautious, naturally slowing down and keeping particular watch for pedestrians and cyclists. The way this is accomplished is by making the driver feel out of place. In a "Complete Street," the boundaries between vehicle right-of-way and the right of way of other traffic is blurred, instinctively causing the drivers to become more alert.

Often these areas are used for city events, or around parks.

Medford Commons, the new center for Street Fairs

One way to cause the drivers to slow down and pay attention is to make them navigate around planters and bends in the road. By putting obstacles in their path, drivers have to exercise more caution when driving, but the visibility is still good for avoiding pedestrians.

A Woonerf design by Hardey Engineering and Assoc.

Using Permeable Pavers

Another way to cause traffic to calm down is to blend the transition between the vehicle right-of-way and the pedestrian right-of-way. In this example, Hardey Engineering & Assoc. used permeable pavers in the road, so that it looks the same as the adjacent sidewalk. The creates the effect of having a crosswalk that is an entire block in length.

5th Street looks similar to the Sidewalk

Another advantage to using pavers in the street is that the texture of the street makes the driver feel as though they are travelling faster. Between the tactile feedback of the tires rolling across the pavers, to the visual effect of having a textured surface moving towards you, the driver has a better sense of how fast they are really travelling.

Right now, the Medford 2013 Pear Blossom Event is just kicking off, so I'm going to head down to the inaugural street fair and go and enjoy my rights as a pedestrian in our very own woonerf system!

Thursday, April 4, 2013

Civil Engineering through history, Part II

Flushed with Pride
As I speak, two of the three toilets in our building are out of service. Apparently there was a recall on the flushing system in our toilets that could cause pressure to build up in the tanks, causing explosions resulting in serious injury from the porcelain shrapnel.

No, seriously! I really wish I was clever enough to make something like that up.

So this week, the theme is on civil engineers' contributions to waste disposal.

Most of us have had the opportunity to visit an outhouse, usually at some Forest Service campground. I always imagined that was the standard fare for people around the world until the 1880’s, when Thomas Crapper made the modern flush toilet a household name, so to speak.

As it turns out, the bronze-age civilization of the Indus Valley Civilization had a flush-toilet in almost every house, with sophisticated city sewer system to carry it all away! (1)

But the Romans really ran with the idea, and developed a standard for waste-water management. They designed and built the Cloaca Maxima (Greatest Sewer) around 600 BC to drain the marshes and clear waste. It remains one of the best known sanitation artifacts of the ancient world. (2) 

If anyone knows where I can visit the museum of sanitation artifacts, I need a date idea for my anniversary.

Pictured: Sanitation Artifact of the Modern World

The wealthy citizens of Rome had toilets at their own homes around 100 AD, with public toilets available for the poor. Most of the time the poor used “chamberpots,” which they emptied by throwing the contents out of a window into the street. Sometimes they even looked to see if anybody was likely to be doused.  It became such a problem that fines were imposed if a person was “injured” by the debris!

Just imagine trying to explain where you got that black eye!

 In his Natural History, Pliny remarked that of all the things Romans had accomplished, the sewers were "the most noteworthy things of all".

That's right. Score one for Civil Engineers.

((1) Rodda, J. C. and Ubertini, Lucio (2004). The Basis of Civilization - Water Science? pg 161. International Association of Hydrological Sciences (International Association of Hydrological Sciences Press 2004).

Thursday, March 28, 2013

Civil Engineering through history part 1

Welcome to the Hardey Engineering & Assoc. Blog.

From the beginning of organized cities, engineers have been hired to solve the basic problems caused by having a bunch of people living together. Fortunately, instead of solving problems through politics, engineers like to take a more hands-on approach.

In ancient Egypt, while the structural engineers were building massive paperweights and getting all the press, civil engineers were focusing on problems like feeding people.

By digging canals, then opening gates that allowed the Nile to flood their fields, the Egyptians could both water and fertilize their crops with ease.

Below is a picture of the Scorpion King ceremonially opening a ditch to start the flooding. (That's a hoe he is holding.)

Herodotus wrote that the Egyptians "get their harvests with less labor than anyone else in the world."

Because of the efforts of the civil engineers in Egypt, the kingdom had enough wealth to leave their mark on history.

More to come: Civil Engineering and waste-water management through history.

Pictured: Solid-waste management during the dark ages. (Or, what  happens when castles are built with no bathrooms.)