Fundamentals of Transportation

As part of the NSF-funded STREET project, we have been putting together ”Fundamentals of Transportation”, a wikibook. I intend to use this next semester as the main text for my Introduction to Transportation Engineering course (CE 3201). We welcome comments and, since this is a wikibook, additions and edits. (Please login using your real name).
This book is aimed at undergraduate civil engineering students, though the material may provide a useful review for practitioners and graduate students in transportation. Typically, this would be for an Introduction to Transportation course, which might be taken by most students in their sophomore or junior year. Often this is the first engineering course students take, which requires a switch in thinking from simply solving given problems to formulating the problem mathematically before solving it, i.e. from straight-forward calculation often found in undergraduate Calculus to vaguer word problems more reflective of the real world.

Agent-Based Model of Price Competition and Product Differentiation on Congested Networks

Recently published:
Zhang, Lei, David Levinson, and Shanjiang Zhu (2008) Agent-Based Model of Price Competition and Product Differentiation on Congested Networks. . Journal of Transport Economics and Policy Sept. 2008 42(3) pp. 435-461. [download]

Using consistent agent-based techniques, this research explores the welfare consequences of product differentiation on congested networks. The economic analysis focuses on the source, evolution, measurement, and impact of product differentiation with heterogeneous users on a mixed ownership network. Path differentiation and space differentiation are defined and measured for a base scenario and several variants. The findings favour a fixed-rate road pricing policy compared to complete pricing freedom on toll roads. It is also shown that the impact of production differentiation on welfare is not always positive and depends on the level of user heterogeneity.

Solar Roadways get prototype funding from DOT

From Autoblog (via Slashdot) Solar Roadways get prototype funding from DOT
I don’t see how this could be cost-effective. 5 billion 12′ x 12′ panels (presumably at less than $100,000 it costs to build the prototype) still has to be pricey (i.e. it would surely be more expensive than a glass window of the same size, so we are talking on the order of $10,000). 5 billion x $10,000 = $500 trillion dollars at a minimum. Mere pocket change, less than my credit limit on my credit cards.

Investing for Reliability and Security in Transportation Networks

Recently published:
Zhang, Lei, and David M. Levinson (2008) Investing for Reliability and Security in Transportation Networks. Transportation Research Record: Journal of the Transportation Research Board #2041 pp.1-10 [doi]

Alternative transportation investment policies can lead to very different network forms in the future. The desirability of a transportation network should be assessed not only by its economic efficiency but also reliability, because the cost of incidental capacity loss in a road network can be massive. This research concerns how investment rules shape the hierarchical structure of roads, and affects network fragility with regard to natural disasters, congestion, and accidents and vulnerability to targeted attacks. A microscopic network growth model predicts the equilibrium road networks under two alternative policy scenarios: investment based on benefit cost analysis or bottleneck removal. A set of Monte-Carlo simulation runs, in which a certain percentage of links are removed according to the type of network degradation analyzed, are carried out to evaluate the equilibrium road networks. It is found that hierarchy exists in road networks for reasons such as economic efficiency, but an overly hierarchical structure has serious reliability problems. Throughout the equilibrating or evolution process, the studied grid network under benefit cost analysis has better efficiency performance, as well as error and attack tolerance. The policy implication from these findings is that benefit-cost analysis should be preferred to myopic bottleneck-removal type of investment rules, no matter how the planning horizon is specified.
Keywords: Transportation network dynamics, road growth model, reliability, vulnerability, fragility, road investment and financing policy

Delta Watch – Cincy negotiating to keep international flights

From Chris Briem at Null Space Delta Watch – Cincy negotiating to keep international flights. Airlines are now threatening to move flights out of cities unless the city guarantees a certain number of passengers or revenue.
Original article here.
This is of course a terrible idea (unless you personally fly direct from CVG to London).
(In 1840 Cincinnati was the the sixth largest city in the US. In 2000 it was 63rd. (the metro area of course is larger, ranking 23rd in 2000). This relative decline is not reversible by direct flights to a few foreign cities.

Determinants of Route Choice and the Value of Traveler Information: A Field Experiment.

Recently published:
Zhang, Lei and David Levinson (2008) Determinants of Route Choice and the Value of Traveler Information: A Field Experiment. Transportation Research Record: Journal of the Transportation Research Board 2086:81-92 [doi]

A major strategy of federal ITS initiatives and state departments of transportation is to provide traveler information to motorists through various means, including variable message signs, the internet, telephone services like 511, in-vehicle guidance systems, and TV and radio reports. This is relatively uncontroversial, but its effectiveness is unknown. Drivers receive value from traveler information in several ways, including the ability to save time, but perhaps more importantly, other personal, social, safety, or psychological impacts from certainty. This information can be economically valued. The benefits of reduction in driver uncertainty when information is provided at the beginning of the trip by various means is the main variable we aim to measure in this research, in which we assess user preferences for routes as a function of the presence and accuracy of information, while controlling for other trip and route attributes, such as trip purpose, travel time, distance, number of stops, delay, esthetics, level of commercial development, and individual characteristics. Data is collected in a field experiment in which more than 100 drivers, given real-time travel time information with varying degrees of accuracy, drove four of five alternative routes between a pre-selected OD pair in the Twin Cities metro area. Ordinary regression, multinomial, and rank-ordered logit models produce estimates of the value of information with some variation. In general, results show that travelers are willing to pay up to $1 per trip for pre-trip travel time information. The value of information is higher for commute and event trips and when congestion on the usual route is heavier. The accuracy of the traveler information is also a crucial factor. In fact, there do not seem be incentives for travelers to use traveler information at all unless they perceive it to be accurate. Finally, most travelers (70%) prefer that such information should be provided for free by the public sector, while some (19%) believe that it is better for the private sector to provide such service at a charge. Over 35% of subjects are willing to pay for OD-customized pre-trip travel time information.
Keywords: Value of Information, Advanced Traveler Information System (ATIS), Real-Time Traffic Operations, Travel Behavior, Spatial behavior, Wayfinding Behavior, Route Choice.

Legibility vs. efficiency

Michael Lewyn on Legibility vs. efficiency
A nice piece on something I have been arguing for a few years.

One reason why buses are less popular than trains is buses’ lack of “legibility”: the ability of an occasional passenger to figure out how to get somewhere by bus.

(For example, the bus stopped running to my workplace because speed bumps slowed the commute by a few minutes).

A few minutes? That’s a lot of speed bumps. More importantly, why are speed bumps being used on roads served by buses?

*Of course, this problem could be alleviated by placing bus
schedules at bus stops, as is frequently done in Toronto and New York City. But I realize that weaker bus systems such as Jacksonville’s may lack the resources for such visionary steps.

Sarcasm appreciated.

Peter Gordon on HSR: How to make a lot of money

Peter Gordon on HSR: How to make a lot of money

“Official 2030 ridership projections are higher than for comaparable systems in Europe and Japan. When airline competition for the LA-SF run heats up, these fares have been known to plummet.
The Simon-Ehrlich wager is well known. Is there anyone out there willing to bet real money on these HSR ridership foreacasts? How about the forecast’s authors?”

This suggests just what we need to ensure more accurate forecasts, payments for forecasts proportional to their accuracy. Forecasters would get paid more if their forecasts were more accurate, less if they lied. The problem is that the forecasters in transportation are looking ahead so far in time, the NPV of the difference may be too small to matter.