From NYT: Architecture – Plan Calls for Rebuilding Haiti Away From Port-au-Prince
“the plan is built around a bold central idea: to redistribute large parts of the population of Port-au-Prince to smaller Haitian cities, many of them at a safe distance from areas most vulnerable to natural disaster. In the process the plan would completely transform Haiti from a country dominated by a single metropolis to what the planners call a network of smaller urban “growth poles.”
“This will only work if these poles become magnets of attraction — with agriculture, tourism, industry and especially jobs,” Mr. Voltaire said. “Otherwise, these people are going to come back.”"
by doing so the planners are forgoing economies of agglomeration at Port-au-Prince. What were the positive externalities that led to massive growth there rather than elsewhere. Do they no longer exist? Can they be replicated elsewhere? Will government be decentralized as well? Will businesses move?
Prompted by the Iranian election where the results were made up on a spreadsheet and violated Benford’s first digit law I was playing with a spreadsheet, and for some reason, decided to count the number of times a set of numbers was evenly divisible by other numbers. (This of course is not Benford’s law at all).
So taking, for example, the numbers from 1 to 1000, the column below “SERIES” indicates that in this set with 1000 entries, the elements are evenly divisible by two 500 times, by three 333 times, etc. which is intuitive.
Taking the cumulative of numbers from 1 to 1000 (so the series is 1, 3=1+2, 6=3+3, 10=6+4, 15=10+5 … 500500=499500+1000), we get the column “CUMULATIVES”. In this case, numbers in this series are evenly divisible by two 500 times, but now threes show up 666 times. Fours are about half of two, and eights are one-fourth of two, and fives are twice tens, but six is half threes, not a third of twos.
The column RATIO is just the ratio of the SERIES and CUMULATIVES numbers.
I am sure there a good intuitive explanation for this fact, and I am sure mathematicians would find it obvious, but it surprised me.
I have no clue if this has any deeper meaning.
|Evenly Divisible by
|none of the above
(none of the above does not imply prime status, but prime numbers will be none of the above).
3/25/2010 – corrected cumulatives column as per J.Horwitz
Answers from my final exam for CE5212/PA 5232 Transportation Policy, Planning, and Deployment from my students. I distilled longer answers to bullet points. Some interesting themes emerge. The class was about half planners, half engineers.
The US Secretary of Transportation has asked you to provide insight into US Transportation Policy. In particular, he wants to know what recommended policy changes you would make to federal surface, air, and water transportation policy (including investment strategies), and why. Use what you have learned in CE5212/PA5232 to recommend 7 to 10 important policy changes, discuss each change, its rationale (giving empirical support where possible), and its drawbacks (e.g. what barriers have prevented implementation). Use examples where appropriate.
renovate and rejuvenate the interstate highway system
separate truck and auto highways
stricter EPA pollution standards
allow international air carriers domestic access
rejuvenate US inland waterways to allow large scale vessels
open surface transportation bill to all modes of surface transportation beyond highways and transit
transition from fuel tax to mileage based user fee
turn airlines into public private partnerships (franchising a la London buses)
reduce power of unions to assign workers at ports
apply antitrust to automakers to increase number of independent companies
slow down the rate of construction of HSR
dedicate more funding to development of smart vehicle and smart road technology
remove barriers to closing or downgrading less valued links
invest in maintenance of existing valued links
implement a mileage based user fee for road users to replace gas tax
decentralize much of federal highway system planning and authority
higher emissions standards
separate cars and trucks where possible
invest in R and D for smart vehicles
more resources for road maintenance
promote transit oriented development
bridge and structure inspection and safety programs
PPP for HSR
improve existing urban rail transit systems, especially mature systems
loosen entry regulation in air transportation
diversity location of ports
invest in innovation
invest in HSR
play more active role in management of airlines
deconstruct freeways that are no longer necessary
increase security in ports
invest in public transportation
shift to VMT tax
Change present road finance system gradually
Support environmentally friendly vehicles
Improve road infrastructure for safety
Implement congestion pricing
Create more jobs in transportation
Dedicate more money to transit
Improve inland waterways
Implement VMT tax to replace gas tax
Create infrastructure bank
Tie federal dollars to implementation of local traffic safety laws
Support TDM with matching funds (a la UPA)
Encourage privatization of local transit services
De-federalize airport security
Focus on accessibility rather than mobility
Change transit CEI
Merge USDOT and HUD
Rationalize US passenger rail system (abandon some link, invest in HSR in high density corridors)
Raise gas tax now and move towards VMT tax in long term
Deploy environmentally friendly cars and infrastructure to support them
Support transit ridership
Break union monopolies on waterfront
Regulate air travel demand (congestion pricing for airports)
Build additional airports
R and D for PRT
More planning and research
Improve management of funds
Alternative funding sources
Break union monopolies on waterfront
Upgrade ATC and aircraft inspection systems
Focus TSA on real threats
Breakdown barriers between engineering and planning
VMT Tax (tax output rather than input)
Decentralize highway revenue (let states tax more, rather than a federal tax disbursed to states)
More R and D
Benefit cost analysis for projects
Allow cabotage and additional deregulation of airlines
Privatize and rationalize Amtrak
Build HSR incrementally to avoid mistakes
Fund urban transit
index gas tax in short term
discourage investment in HSR (problem is urban, and Benefit cost analysis does not warrant)
reallocate HSR funding to LRT
Objective analysis of which LRT to invest in
Support green roads
R and D for intelligent vehicles
Support alternative fuel production
Find alternatives to gas tax
Prioritize mass transit funding
Multimodal transportation fund
More funds to improve safety
More rigorous drivers license program
More R and D
Rationalize government programs in transportation (fewer organizations)
Breakdown barriers between engineering and planning
Stronger environmental regulations
Decentralize highway authority (let states tax more, rather than a federal tax disbursed to states)
Objective process for determining transportation susbsidies
Raise and index gas tax
Use VMT tax for hybrid and electric cars
Distribute federal gas tax back to states in proportion to where it is generated
Invest in separate facilities for cars and trucks to improve safety
R and D for intelligent vehicles and roads
Federal transit dollars should not just fund large capital but also bus operating and maintenance costs
Partially nationalize air transportation system
Improve port security
Zhang, Lei and David Levinson (2010). Ramp Metering and Freeway Bottleneck Capacity. Transportation Research: A Policy and Practice 44(4), May 2010, Pages 218-235.
This study aims to determine whether ramp meters increase the capacity of active freeway bottlenecks. The traffic flow characteristics at 27 active bottlenecks in the Twin Cities have been studied for seven weeks without ramp metering and seven weeks with ramp metering. A methodology for systematically identifying active freeway bottlenecks in a metropolitan area is proposed, which relies on two occupancy threshold values and is compared to an established diagnostic method – transformed cumulative count curves. A series of hypotheses regarding the relationships between ramp metering and the capacity of active bottlenecks are developed and tested against empirical traffic data. It is found that meters increase the bottleneck capacity by postponing and sometimes eliminating bottleneck activations, accommodating higher flows during the pre-queue transition period, and increasing queue discharge flow rates after breakdown. Results also suggest that flow drops after breakdown and the percentage flow drops at various bottlenecks follow a normal distribution. The implications of these findings on the design of efficient ramp control strategies, as well as future research directions, are discussed.
(pre-print available here.
(For those of you who give up hope after rejection, this paper was first submitted in 2003! My co-author earned an MS, another MS, a Ph.D. and has held two faculty positions over the duration of this article. I myself have had 3 children. After various recommendations for revise and resubmit, and changes of editor, it was lost twice by the (previous) editor of TRa (prior to the electronic submission system, which at least removes one excuse from the editor’s arsenal), and had been accepted before it was lost so had to go through re-review after the change in editorship. I think it is quite interesting and the analysis and results hold up, and so I encourage you to read it and cite it if it is relevant to your work. The final review process was relatively fast, taking 17 months from resubmission to print. And only 13 months from resubmission to online.)
H/T D.K. James Fallows writes: Two Notes on Infrastructure and Going to Hell
… Delaware’s two distinguishing traits: shamelessly milking I-95 traffic with highway-robbery toll booths, and cell-phone black hole, at least near Amtrak routes. Maybe they’re mad about the lost tolls.
Indeed, Delaware achieves more of its transportation revenue from tolls than any other state. Why do they do this? As my dad would say “because they can.” They probably have a greater share of through (non-resident) trips on their roads than any other state, being the second smallest. See Levinson, David (2001) Why States Toll: An Empirical Model of Finance Choice. Journal of Transport Economics and Policy 35(2) 223-238 (May).
From ‘BBC’ (of the ‘single quote’ indicating nothing) New York airport jets ‘directed by child’
US officials are investigating how a child was apparently allowed to direct planes at New York’s JFK airport – one of the country’s busiest.
If I were that kid I that would have been so cool.