Number Crunching in Transport

Friday, July 2, 2010


Sudhir Gota

A latest report claims that Beijing has the worst traffic in the world. In this study, nearly 8,192 motorists in 20 cities on six continents were surveyed so as to find out if the traffic has gotten worse in past three years?  
The index suggested is comprised of 10 issues: 
1) commuting time, 
2) time stuck in traffic, 
agreement that: 3) price of gas is already too high, 4) traffic has gotten worse, 5) start-stop traffic is a problem, 6) driving causes stress, 7) driving causes anger, 8) traffic affects work, 9) traffic so bad driving stopped, and 10) decided not to make trip due to traffic. 
The cities scored as follows: Beijing: 99, Mexico City: 99, Johannesburg: 97, Moscow: 84, New Delhi: 81, Sao Paolo: 75, Milan: 52, Buenos Aires: 50, Madrid: 48, London: 36, Paris: 36, Toronto: 32, Amsterdam: 25, Los Angeles: 25, Berlin: 24, Montreal: 23, New York: 19, Houston: 17, Melbourne: 17, Stockholm: 15.

My reactions on the report
1. The problem with such indicators is that it looks at only motorized traffic ignoring the daily commute of people by non motorized modes of transportation. Commuting is not only driving and this makes this index a poor quantifier.  Look at the below graphic where we have captured trip mode shares of NMT users. Its nearly 1/3 total trips in the city even with poor data capturing.

2. “As for a reduction in travel stress, 36% of the respondents said that improved public transportation would help. Beijing topped the list here (65%), followed by Milan (57%), New Delhi (53%), Sao Paolo (52%), and Paris (51%).” – Reconfirms the fact that Public transportation is the key. 
3. “ When asked whether traffic had harmed their health in any way, 57% said yes. Among those who said it had, increased stress (30%) and anger (27%) were the primary manifestations. Increased stress was most prominent in Mexico City (56%), Sao Paolo (55%), New Delhi (45%), Buenos Aires (44%), and Beijing (40%), while anger prevailed in Beijing (53%), Moscow (51%), New Delhi (48%), and Mexico City (43%). All of these cities were among those identified in the survey as having especially painful commutes.” -  being forced to breathe polluted air is more critical than stress and anger as it has long term impact. 
4. “If their commuting time could be significantly reduced, 53% said they would spend more time with friends or family, 44% would devote themselves to more recreation, and 42% would spend more time exercising. And 16% said they would work more (multiple answers were allowed).” – This is critical as it may change the way we quantify travel time savings as normally we quantify travel time benefits by assuming that people would work based on times saved. I am more interested in knowing about travel time budgets and what purists would think of that based on current travel time of 2-4 hours/commuter/day?. The report claims that “The average delay was one hour – very similar to the figure for the U.S. alone in the previous two Commuter Pain surveys conducted by IBM.”
5. When commuters cancelled a recent planned driving trip, the destination was work 24% of the time, recreation 22%, and shopping 21%.” -  was this really a loss?  One driving trip cancelled would have induced one additional trip in the system and did they use telecommuting? 
6. “Gas prices, notably in flux in recent years, appear to have a potential bearing on the willingness of commuters to drive to work. About a quarter of the respondents said that gas prices would have to rise by 20-30% for them to seriously consider other forms of transportation. A large proportion of the respondents (47%) thought that gas prices are already too high. Cities in which this feeling was particularly acute were Amsterdam and Madrid (66%) and Buenos Aires (64%). Cities in which it was relatively absent were New Delhi (24%), Moscow (31%), Los Angeles (36%), and Houston (39%) – perhaps suggesting that at least a modest rise in gas prices would not much affect traffic in those cities.”  -  Switch to which mode is the main factor? 

Driving being a pain may not be a valuable indictor for bad transportation. Sometimes it can be argued that driving being painful and stressful is a perfect recipe for success.   

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