Dr. Bahman Lahoorpoor

Bahman Lahoorpoor

Congratulations to Dr. Bahman Lahoorpoor for “satisfying the requirements for the award of the degree of Doctor of Philosophy at the University of Sydney.”

Thesis Title:  “Terraces, Towers, Trams, and Trains : Examining the Growth of Sydney using Empirical Models and Agent-based Simulation

Lead Supervisor: Professor David Levinson.

Abstract: Transport networks and land use are inter-dependent. This joint co-development process of infrastructure and building location is often theorised to be a positive feedback cycle: transport infrastructure produces accessibility that induces land development, which induces transport demand and increases accessibility, increasing the production of transport networks (i.e. inducing supply) and further intensifying land development. In Chapter 2 we investigate the critical elements of this dual connection between land use and transit. Sydney as a good example of a rapidly developing city, had public railway transport services beginning in the 1850s, which facilitated and responded to the development of suburbs. Chapter 3 explains how the historical railway network, including trams and trains, and historical population data are collected and digitised. A series of network characteristic measures and a metric for characterising the population distribution are also presented. In Chapter 4 we test whether trams expanded accessibility relative to buses by comparing the services provided by historical trams, the replaced bus services, and the remaining train and light rail networks. We compare 1925, when the tram system was at its peak, and 2020. In Chapter 5 we investigate the theory of interaction between land use and the transit network. We investigate the direct and indirect links between land development and transit investments using the concept of accessibility. We develop an empirical model to capture the Greater Sydney area’s historical evolution of land use and public transit networks. In Chapter 6 we develop a simulation framework to replicate the growth of railway networks by given exogenous historical evolution in land use. The framework is an iterative process that includes five consecutive components including environment loading, measuring access, locating stations, connecting stations, and evaluating connections.

Publications by Bahman Lahoorpoor include:

  • Lahoorpoor, B. and Levinson, D. (2022) In Search of Lost Trams: Comparing 1925 and 2020 Transit Isochrones in Sydney. Findings, March. [doi]
  • Lahoorpoor, B., Rayaprolu, H., Wu, H., and Levinson, D. (2022) Access-oriented design? Disentangling the effect of land use and transport network on accessibility. Transportation Research Interdisciplinary Perspectives. [doi]
  • Lahoorpoor, B., Rayaprolu, H., Wu, H., and Levinson, D. (2022) Prioritizing active transport network investment using locational accessibility. TeMA – Journal of Land Use, Mobility and Environment (in press)
  • Rayaprolu, H., Wu, H., Lahoorpoor, B., and Levinson, D. (2022) Maximizing Access in Transit Network Design. Journal of Public Transportation. 24. [doi]
  • Wang, Yingshuo, Lahoorpoor, B. and Levinson, D. (2022) The Spatio-temporal Evolution of Sydney’s Tram Network Using Network Econometrics. Geographical Analysis. [doi]
  • Lahoorpoor, Bahman and Levinson, D. (2020) Catchment if you can: The effect of station entrance and exit locations on accessibility. Journal of Transport Geography. 82, 102556. [doi] [full report]

The Transportation Experience: The Video Experience

I have used The Transportation Experience as a primary text for my Transport Policy, Planning, and Deployment class at Minnesota and Sydney for a number of years, and a few other schools use it as well. Over that time, the presentation has evolved. In 2019 I decided to flip the class for 2020, so it would be less of me lecturing, and more interactive. That proved fortuitous planning, as we soon went online, and asynchronous lecturing became standard.

There is no good reason to keep the videos bottled up, knowledge should be free.  I don’t think I will lose any students or book sales by making these videos available more widely, so I am making them available more widely.

To that end, the videos accompanying The Transportation Experience are now online, you can find the YouTube Playlist below, and the specific videos by chapter listed in the Table of Contents. Happy viewing.




Table of Contents

(with accompanying [Video] links)

Preface  [Video]

Part One – Wave One: 1790–1851
1. Rivers of Steam [Video]
2. Design by Design: The Birth of the Railway [Video]
3. The Turnpike Era [Video]

Part Two – Phase 1 of the Life-Cycle
4. Inventing and Innovating [Video]

Part Three – Wave Two 1844–1896
5. Maritime Modes [Video]
6. Railroads Deployed [Video]
7. Good Roads [Video]
8. Transit [Video]
9. Telegraph [Video]

Part Four – Phase 2 of the Life-Cycle
10. Magic Bullet  [Video]

Part Five – Wave Three 1890-1950
11. American Shipping  [Video]
12. Taking Flight [Video]
13. Railroads Regulated [Video]
14. Bustitution [Video]
15. Public Roads [Video]
16. Urban Planning: Who Controls the Turf?  [Video]
17. Telephone  [Video]
Part Six – Phase 3 of the Life-Cycle
18. Aging  [Video]
Part Seven – Wave Four: 1939-1991
19. Logistics  [Video]
20. The Jet Age [Video]
21. Railroads Rationalized [Video]
22. Interstate [Video]
23. Recapitalization [Video]
24. Lord Kelvin’s Curse [Video]

Part Eight – Life-Cycle Dynamics
25. Lifecycle [Video]
26. Meta-cycles [Video]

Part Nine – Wave Five: Modern Times
27. Energy and Environment [Video]
28. Higher-speed rail [Video]
29. Internet [Video]
30. Technology: Hard and Soft [Video]

Part Ten – Beyond the Life-Cycle
31. Policy [Video]
32. Speculations [Video]

Part Eleven – Afterwords: Reflections on Transportation Experiences
33. I-35W [Video]
34. Design of a Life [Video]
35. Commencement [Video]

Part Twelve – End Matter

The videos were produced by Bahman Lahoorpoor, who synchronised audio and video, and helped extend the slides I had previously had. 

Original intent and the right to bear arms

Flintlock musket

The controversial Second Amendment of the Bill of Rights says:

“A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.”

There is much controversy over whether the state can regulate the right to ownership and so on, and usually it goes back to what the founders meant about “A well regulated Militia, being necessary to the security of a free State”. I think its pretty clear the founders intended for “the people” (i.e. white men) to have guns, in case they needed to be pressed into service to fight native Americans, prospectively rebellious whiskey distillers, or the British.

Flintlock Pistol

A friend of mine points out that far less attention is paid to what is meant by the term “Arms”. If we go back to original intent, the word “Arms” in 1791 meant armaments that were available in 1791. For instance, few argue citizens should have a right to an atomic bomb. The founders did not conceive of those weapons as falling into the rubric of Arms, and probably would not have supported that if it did. Their view of Arms was informed by the recently completed Revolution. The arms that were available during the revolution include  the Flintlock Musket. Notably, interchangeable parts were not even established yet, so these were handmade.

So if you want to argue original intent, go for it, just accept that only handmade weapons available prior to 1791 are constitutionally protected. If you argue original intent, you argue the constitution guarantees people  their cross-bow, sword, musket, and bayonet, but fails to protect more recent weapons.


Happy 70th Birthday, Highway Statistics

There is one thing bureaucracies do better than any other organization, and that is keeping data series alive. I recently discovered the archives of the Highway Statistics series have been digitized by the Office of Highway Policy Information (OHPI). The first Highway Statistics, put out by the Public Roads Administration and Federal Works Administration in 1945 (pdf). Remember, they did this before computers, even before mainframes, so the staff effort must have been enormous.

Trend in Motor Vehicle Registration and Gasoline Consumption, 1945 Highway Statistics
Trend in Motor Vehicle Registration and Gasoline Consumption, 1945 Highway Statistics

The full archives (pre 1995) can be found here. More recent statistics can be found here.

In 1945 there were fewer than 34 million vehicles registered in the US. Today (2012, the most recent year available) that number is about 253 million. (7.4 times)

In 1945 gasoline consumption was about 22 billion gallons. Today that number is 169 billion. (7.7 times).

Consumption per vehicle is about 667 gallons per vehicle today, compared with 647 in 1945. Of course fuel economy is up, as is miles per vehicle.

Then and Now: University of Minnesota | streets.mn


Streetcar on Washington Avenue in front of Coffman Union c. 1953
Streetcar on Washington Avenue in front of Coffman Union c. 1953

A photo taken from the second floor of Coffman Union on September 26, 2014.
A photo taken from the second floor of Coffman Union on September 26, 2014.

These images show very little change on the main Mall of the University of Minnesota campus. Coffman still looks down at Northrup in the distance. There is a tree in the middle, so the landscape is slightly less formal. Some new buildings have been built at the edge of the Mall and Washington. Washington is deeper entrenched.

But lots of more important changes have occurred. After about 60 years without rail transit on Washington Avenue, it came back in 2014. Private cars no longer drive on Washington – which is now a mall. The wooden bridges across Washington are now metallic. Sheltered bus stops grace Washington.

But the unseen scene shows lots of changes.

Students dress more casually. The ethnic composition of students is very different. I am taking a picture with a camera in a mobile telephone, which every person in this scene probably has. The truck in the foreground is due to the bookstore sidewalk sale. The transit is publicly owned. There are “Health Partners” which manage your health instead of private doctors.  The world is now in color.

Cross-posted at streets.mn.

The forgotten discovery of gravity models and the inefficiency of early railway networks

Andrew Odlyzko finds the earliest use of gravity models for travel demand and spatial interaction in his new working paper “The forgotten discovery of gravity models and the inefficiency of early railway networks“, moving the clock a few years earlier.

Abstract. The routes of early railways around the world were generally inefficient because the prevailing doctrine of the time called for concentrating on provision of fast service between major cities and neglect of local traffic. Modern planners rely on methods such as the “gravity models of spatial interaction,” which show the costs of such faulty assumptions. Such models were not used in the 19th century.
The first formulation of gravity models is usually attributed to Henry Carey in 1858. This paper shows that a Belgian civil engineer, Henri-Guillaume Desart, discovered them earlier, in 1846, based on the study of a unique and extensive data set on passenger travel in his country. His work was published during the great Railway Mania in Britain. Had the validity and value of this contri- bution been recognized properly, the investment losses of that gigantic bubble could have been lessened, and more efficient rail systems in Britain and many other countries would almost surely have been built. This incident shows society’s early encounter with the “Big Data” of the day and the slow diffusion of economically significant information. The methods used in the study point to ways to apply methods of modern network science to analyze information dissemination in the 19th century.

Lord Gordon-Gordon | streets.mn

Cross-posted from streets.mn Lord Gordon-Gordon.

Lord Gordon-Gordon (a.k.a. Lord Glencairn, Hon. Mr. Herbert Hamilton, George Herbert Gordon, George Gordon, George Hubert Smith, and John Herbert Charles Gordon) migrated from Britain to North America in 1870. He was not a Lord, as many Americans and Canadians later learned, merely impersonating a Scottish peer to borrow money to buy land. He landed in Minnesota in 1871, and deposited £20,000 in a local bank, establishing legitimacy. He promised to invest $5 million to help resettle 100 Scottish families on land managed for the Northern Pacific Railroad. Col. Loomis, the land commissioner for the Northern Pacific spent $45,000 touring with Lord Gordon-Gordon through rural Minnesota.

Lord Gordon-Gordon

“He who sells what isn’t his’n, must buy it back or go to pris’n.” – Daniel Drew (attributed)

Beginning with the New York & Harlem Railroad, Cornelius Vanderbilt started accumulating a network to connect New York with Chicago, which by 1870 comprised the New York Central & Hudson Railroad, then valued at $100,000,000, the most successful of the Northeast lines, which was able to pay dividends through the Panic of 1873. His methods were harsh. He cut off feeder traffic to force a downstream company into his control. He cornered the market in stocks to punish short-selling public officials.

Short-selling is selling stocks you don’t own with the hope of buying them back later at a lower price, and is in contrast with going long on a stock, or buying it with the expectation it will rise in price. Clearly if the price does not fall, a short-seller will lose money. If someone can acquire a majority of the outstanding stock, and an insufficient amount of stock is available for short-sellers to purchase, their losses can be astronomical. In one of his few failures, Vanderbilt got into a bidding war over the Erie Railroad.

The “Erie War” brought together a cast of some of America’s most important financiers and railroad men in a battle over a second-tier railroad.

Daniel Drew (1797-1879) was once Vanderbilt’s partner. He became a stock-broker in 1844, and joined the Board of the Erie RR in 1857. He shorted the stock of New York & Harlem RR, and lost a fortune in 1864. After the Erie War with Vanderbilt, in 1870 Fisk and Gould then played Drew, causing him to lose $1.5 million. The Panic of 1873 was no aid, and Drew filed for bankruptcy and died penniless.

James (Diamond Jim) Fisk (1835-1872) made his first fortune dealing in Army contracts in the US Civil War. While he lost this wealth in speculation, after the War he worked for Daniel Drew’s brokerage. The famous Black Friday of 1869 resulted from Fisk and Gould’s failed attempt to corner the Gold Market. After the Erie War, Fisk had a scandalous affair with showgirl Josie Mansfield which ultimately broke off when Mansfield took up with Fisk associate Edward Stokes, who then attempted to blackmail Fisk for his illegal doings. Fisk had no part of that, and Stokes killed Fisk in 1872 (and went to prison for 4 years). Fisk was remembered as a populist loathed by high society.

Jay Gould (1836-1892), about the same age as Fisk, but much younger than Drew, was a surveyor and historian, and then formed a tanning business. It was the Panic of 1857 which moved him to high finance, when he bought out his partners’ properties for himself. As with any good, on-the-edge capitalist, this led to some violent kerfuffles, but Gould profited, and soon used his profits to invest in the Rutland & Washington Railroad. He acquired a reputation of being able to move markets by cornering the market in Gold in 1869, culminating in Black Friday, when the price of Gold collapsed. After the Erie War, and then being forced out of that railroad, he acquired the Missouri Pacific, Union Pacific, and Western Union, and transit routes in New York City. among other properties. At one time he held 15% of all US rail mileage. When crushing the 1886 Great Southwest Railroad Strike, he is reported to have said “I can hire one-half of the working class to kill the other half.”

These three: Daniel Drew, one-time partner of Cornelius Vanderbilt, James Fisk, and Jay Gould illegally issued “watered-down” stock in the Erie Railroad, much of which was purchased by Cornelius Vanderbilt who was aiming to get control. Watered-down stock entails the issuing of additional stock in a company, increasing the company’s par value. Suppose a company had issued 10,000 shares of stock initially in exchange for $10,000 of capital. The stock would be watered if the company acquired say $1,000 of additional real assets in exchange for $2,000 in stock. The value of the other stock would in reality be worth less (since the total company assets were now $11,000 but there were 12,000 shares outstanding, each share was only worth $0.91 instead of $1.00. This procedure is no longer done (as such) since par value is now nominal on companies, and the last court case involving watered stock was in 1956.

The more control Vanderbilt wanted, the more stock Drew, Fisk, and Gould issued, costing Vanderbilt $7 million between 1866 and 1868. While much of that was repaid to Vanderbilt, Gould himself could not retain the Erie. This was due to a strange immigrant.

Lord Gordon Gordon

Lord Gordon-Gordon (a.k.a. Lord Glencairn, Hon. Mr. Herbert Hamilton, George Herbert Gordon, George Gordon, George Hubert Smith, and John Herbert Charles Gordon) migrated from Britain to North America in 1870. He was not a Lord, as many Americans and Canadians later learned, merely impersonating a Scottish peer to borrow money to buy land. He landed in Minnesota in 1871, and deposited £20,000 in a local bank, establishing legitimacy. He promised to invest $5 million to help resettle 100 Scottish families on land managed for the Northern Pacific Railroad. Col. Loomis, the land commissioner for the Northern Pacific spent $45,000 touring with Lord Gordon-Gordon through rural Minnesota.

While still leading Minnesota on, Lord Gordon-Gordon, using letters of introduction from Col. Loomis, soon moved to New York. On the train ride east, he befriended the wife of James Fisk. In 1872, he convinced Gould that he and his European friends already owned some 60,000 shares of the Erie RR and he could help Gould acquire control of the Board of Directors of the Erie Railroad, in exchange for $1 million in stock as part of a “pooling of interest.” Upon receiving the stock, Gordon-Gordon promptly sold it, worsening Gould’s position. Gould sued, and Gould’s friends in New York City Hall (then under the reign of their ally and Erie RR fellow Board member, Boss Tweed) had Gordon-Gordon arrested. But Gordon-Gordon made bail based on the reputation of his purported European friends, and promptly fled to Manitoba, before such information could be confirmed, and before his history caught up with him.

“600 shares of Erie, some 1,900 of corporations affiliated with Erie, and 4,722 of the Oil Creek and Allegheny Valley Railroad, twenty-one thousand dollar bonds of the Nyack and Northern Railroad, and $160,000 in currency. The careful recipient of these securities and cash presently found an error of forty thousand dollars in the footing of Gould’s memorandum and sent word of the shortage. Gould did not think there was such an error, but under the circumstances he would not dispute the point and came back with an additional forty thousand dollars in cash. To a modest request for a memorandum receipt, his lordship replied with exceeding dignity that his word of honor ought to be receipt enough, and handed the bundle back to Gould. Gould took it, went as far as the door, returned, laid it down, and departed in faith that his property was in safe hands. It must have been sheer sport in playing a fish which had taken his hook so greedily that led Gordon to demand that Gould separate himself from the old directorate. On March 9 Gould delivered to him his resignation as director and president of the Erie Railroad Company, to take effect upon the appointment of his successor. The great covenant was complete.” (Folwell 1921)

Gordon-Gordon offered to buy large parts of Manitoba from the government, which appealed to locals there, but soon his American enemies found out and sent a posse of bounty-hunters to bring him back to the US. This posse included 2 future Governors of Minnesota and 3 future members of Congress. They successfully kidnapped Gordon-Gordon but were stopped by the Mounties in Winnipeg and put in prison themselves. The Governor of Minnesota put the state militia on alert and President Grant authorized sending an army into Manitoba, and a major international incident between Canada and the US was threatened. To avoid conflict, Canada released the posse, but Gordon-Gordon was already freed. Then his European enemies asked for his extradition on similar charges of swindling a jeweler of £25,000, and Canada agreed. Making his escape again, he was again arrested, and again released on bail. But before his extradition in 1874, he held a party, gave gifts to his local friends, and then shot himself.

Gould’s loss of $1 million in stock may have been sufficient to cost him the Erie Railroad.


Folwell, W. (1921). History of Minnesota, Volume 2. Minnesota Historical Society Press.

Johnston, J. (1950-51). Lord Gordon Gordon. Transactions of the Manitoba Historical Society Series 3.

Adapted from Garrison, W and Levinson, D (2014) The Transportation Experience: Second Edition. Oxford University Press.


Fourth of July 1999 – Stone Arch Bridge | streets.mn

Cross-posted at streets.mn Fourth of July 1999 – Stone Arch Bridge

Fourth of July 1999 – Stone Arch Bridge

I had just moved to Minnesota as a new Assistant Professor, and was living in the Marcy-Holmes neighborhood. On the July 4, 1999, I decided to see the fireworks at the nearby Stone Arch Bridge. I went early, enjoyed the warm summer’s afternoon, and slowly the crowd began to fill in this prime spot for fireworks viewing. There were couples, families, people of all ages, races, and stages of inebriation. On one side of me was an immigrant south-Asian family (the women in traditional costume), including a mom and her newborn child. On the other side a fifty-something guy (my guess a native Minnesotan), a bit on drunk side, with his girlfriend or second wife. 
It’s about 8:30 pm, well before the fireworks get going, and the guy thought it would be fun to launch his own rockets off the north/east side of the Bridge. Having seen real fireworks, I never understood the need of people to launch their own, which are mere sparklers in comparison. The first rocket shoots off, makes some sort of pop noise, and there it goes into the water. The second he shoots off and it for some reason boomerangs back to the Bridge, whizzing by (and scraping) me (leaving burn-marks on my shirt) and lands on the blanket the south-Asian mom has laid out. It starts a small fire, which she puts out by beating it with her sandal.Minneapolis's Stone Arch Bridge, Fall 1999

I am pissed, but she is furious, since it missed her baby by inches. The crowd, led by the mom, but including everyone else around starts yelling at the guy, basically asking the rhetorical question “what the hell is wrong with you? Get out.”. He stands there unfazed as a lynch mob begins to form, and he sort of shrugs. The yelling gets louder. His lady whispers to him to the effect that they better leave, and she escorts him off the bridge.

The riot was averted, and the real fireworks proceeded apace. They looked something like this:

I have not returned to fireworks at the Stone Arch Bridge, my preferred location is now Tower Hill, which is not nearly so close to the action, but let’s you see almost every firework display in the Metro area. Unfortunately the Hill is infested with mosquitos and smokers this time of year.


Does TTI underestimate historic congestion levels?

To read the Texas Transportation Institute’s Urban Mobility Report is to believe congestion has more than doubled since 1982 (really between 1982 and 2000). From one perspective, of course congestion must have risen, demand (Vehicle Miles Traveled, Population, etc.) increased significantly over this period while supply (Lane Miles of Road Capacity) did not increase at nearly the same rate.
But I was alive in 1982, I was in cars at that age (and driving myself the next year) (in Central Maryland). I remember congestion in the 1980s. To misquote Lloyd Bentsen, “Congestion was a friend of mine”, and TTI seems to be saying to 1982 “You’re no congestion”. But congestion doesn’t seem appreciably different from today. People complained about it then as much as now. Some bottlenecks have been fixed, new ones have emerged.
So I wonder whether congestion did, in fact, “double”.
Some hypotheses:
1. Measurement issues. Continuous roadway travel time measurements were a lot scarcer in the 1980s than today. Freeways now have loop detectors on every segment, whereas there might have been a permanent recording station every 5 or 10 miles in the 1980s, so a lot more had to be estimated and approximated. There are still no good arterial measurements, the most recent Urban Mobility Report uses GPS data from Inrix, and this will clearly come to dominate congestion measures. Notably, including this measurement forced TTI to re-estimate downward their historical congestion measurements.
2. Definition: As noted by Joe Cortright’s report Driven Apart, mobility is not accessibility. A city where I can reach everything in 10 minutes, but travel at 30 MPH (when freeflow is 60 MPH) is more congested than one where I can reach everything in 30 minutes, but can travel at freeflow conditions. The TTI in a sense penalizes efficient land uses.
3. Induced Demand: Highway expansion tends to get used up (this is not a bad thing of itself, just a thing), so much of road expansion gets eaten up in more traffic. Similarly highway reduction reduces travel. Duranton and Turner write “We conclude that an increased provision of roads or public transit is unlikely to relieve congestion.”
This does not explain why congestion is under-estimated in the past though.
4. Congestion vs. Speed: Travel times on journey to work increased only marginally over this period. Average distances for trips rose faster than travel times, indicating average travel speeds increased. So even with increasing congestion, if travelers shifted to relatively faster (e.g. suburb to suburb freeways) from slower (e.g. suburb to city arterials), congestion can rise on each link, but travel speeds still increase. See The Rational Locator for an example of this.
5. Perspective: This previous point about perception can be refamed as one of perspective. There are differences between spatial averages (which TTI uses) and person-based averages (which individual observers perceive). So the person based average for any metropolitan resident may be the same, but the amount of space (network) covered by congestion may increase if the total amount of space which is developed increases. Similarly, if there is peak spreading, congestion occurs over a longer duration.
However, TTI is not simply saying that the amount of area that is congested increased, they are claiming, for Washington DC the delay per person increased from 20 hours per year in 1982 to 74 hours in 2010.
I am willing to believe that with recent measurements, 74 hours per year for an average commuter in DC is plausible in 2010, since that is just under 10 minutes each way each day for 225 work days per year. 10 minutes of delay on a 30 minute commute means the freeflow time on that commute (un-delayed, e.g. Sunday morning) was 20 minutes. This seems about right for the “average” commuter. Rush hour is when everyone has to slow down.
But this implies in 1982 that delay was less than 3 minutes a day per commuter each way. That seems unreasonably small when you think about it, I could have spent 3 minutes at a traffic light in DC at the time, and that certainly constitutes delay. They are saying for every person who had a 10 minute delay, 2 people had 0 delay to get an average 3 minute delay, and that is not the metropolitan Washington I was familiar with. Congestion was sufficiently important than that radio stations had regular traffic reports, and traffic helicopters, it was not something insignificant.
Of course this is impossible to fully validate, as we cannot go back in time and accurately measure speed. The best I could think of was using the Google NGram feature to track mention of some keywords in books. This proves nothing unfortunately, and suggests a small uptick in the word “traffic” in the 1990s, but is interesting none-the-less.
One however can imagine the motivation for wanting congestion to appear lower in the past than it actually was. This means congestion is rising faster, and thus creates a greater claim on the public weal than if congestion were always with us at roughly the same level.