[sustran] Re: Article in Guardian Newspaper

[Alan Patrick Howes]

The main message is, if you are trying to judge the value of a bus lane in a particular location, use figures that are appropriate to the scheme in question - not averages. And look at the whole picture, not just the productivity of the road section in question.
 
Bus lanes don't get put in "average" locations, they get put where bus loads are heaviest - or they should do. I am rusty on my traffic engineering, but isn't that figure of 1,700 autos per hour per lane a peak figure, rather than an average? It's certainly a lot higher than the 24-hour system-wide AVERAGE per lane flow in any city I can think of!
 


--
Alan P Howes, Special Transport Advisor,
     Dubai Municipality Public Transport Department
aphowes at dm.gov.ae
http://www.dubaipublictransport.ae/
Tel:    +971 4 286 1616 ext 214
Mobile: +971 50 5989661


-----Original Message-----
From: Jack Mallinckrodt [mailto:mally at ieee.org]
Sent: Sun, 30 March, 2003 11:17
To: sustran-discuss at jca.ax.apc.org
Cc: sustran-discuss at jca.ax.apc.org
Subject: [sustran] Re: Article in Guardian Newspaper


At 08:38 PM 3/29/03, Alan Patrick Howes wrote:


I smell disinformation!
 
Let's leave aside for the moment such questions as the safety and environmental effects of 1,700 autos per hour vs 231 buses per hour, and the effects on congestion on the rest of the traffic system - which are major considferations.
 
But even then - 11 persons per bus?! Our AVERAGE occupancy (passenger-kms/vehicle-kms) here is 20.5, and that includes some minibus routes. I would expect figures in Mumbai to be much higher. And if we had bus lanes (dream on!) they would be in places where the occupancy was higher still - perhaps 40 average and 50+ in the peak. Which even on Jack's limited criteria changes the picture dramatically. Jack - is that figure of 11 an overall US all-day average, or a figure for bus lane sites, or what?


JM: I have found that there is a tendency to overestimate bus ridership when treated as an eyeball or off-the-cuff estimate. The figure of 11 persons per bus is accurate.  It is from the DOT, FTA, US National Transit Database, 2001, for all times of day, all bus system opertors, all bus types, and is derived as
AVO = US Annual Bus Passenger miles / US Annual Bus Revenue hours
   = 1.83E11/1.65E9 = 11.09 passengers/bus. 

That is quite an accurate number for the US average and has been about the same for the last ten years.  Comparable peak hour AVO numbers are not available. And As I said in my post, you'll have to use your own figures. 

Peak hour loadings are certainly higher but they are so for both buses and for roads, so the comparison of day average persons/hour should  be indicative. 




You can certainly look at traffic flow like it was analagous to electricity distribution - the more down the pipe the better - but that is only a fraction of the proper picture if your goal is a "livable city". Take a look at Jack's website Debi ( www.urbantransport.org) and you will see where he is coming from - then make your own judgement on the value of his advice in your situation.


Evidently Alan, you decide what to believe based on the credentials of who says it.  I prefer, to make my arguments stand on their own valid data and logic. If that doesn't cut it with you, so be it.  

Jack 
  


I don't know the full picture, but I suspect the problem in Mumbai is more one of politics than planning.
 
--
Alan P Howes, Special Transport Advisor,
     Dubai Municipality Public Transport Department
aphowes at dm.gov.ae
http://www.dubaipublictransport.ae/
Tel:    +971 4 286 1616 ext 214
Mobile: +971 50 5989661 


-----Original Message----- 

From: Jack Mallinckrodt [ mailto:mally at ieee.org] 

Sent: Sat, 29 March, 2003 21:16 

To: sustran-discuss at jca.ax.apc.org 

Cc: sustran-discuss at jca.ax.apc.org; gh7 at york.ac.uk; Matoff, Tom; vuchic; Francis Vanek; Ritjavakhtar at aol.com; oeyvind.espe at ps.ge.com 

Subject: [sustran] Re: Article in Guardian Newspaper



At 05:47 AM 3/29/03, Debi Goenka wrote:





We are trying to get some buslanes in Mumbai, and I would like to get some answers. The standard response to bus lanes in Mumbai is that the existing roads are not wide enough - my answer is that in such cases, perhaps such roads should be reserved exclusively for buses!

JM: Well, maybe so, maybe not, but that should be based on comparison of how many persons per day the bus system would carry vs for the corresponding roadway. And that is exactly the same kind of calculation I was illustrating for light rail. 



To compare bus vs automobile in the same way compute 

PPHbus = BPD x BAVO 

PPHauto = APD x AAVO 

where BPH = buses per hour past an average point along the busway 

      APH = Autos per hour past an average point along the road 

      BAVO = Average Vehicle Occupancy of a bus, persons/bus 

      AAVO = Average Vehicle Occupancy of an auto,persons/auto. 

The mode providing the higher PPH count is more productive. 

For example, using typical US numbers, if the roadway lane were to carry 1700 vehicle/hour at an average vehicle occupancy of 1.5 persons/vehicle, the roadway would be carrying 2550 persons/hour. In the alternative, if the average bus occupancy were 11 persons/bus, you would have to run 231 buses per hour, or one every 15 seconds to provide equivalent transport volume, 2550 persons/hour. 



All the above numbers are typical for US, except for the 231 buses per hour which is very high. You should make this calculation for your own numbers for Mumbai. But for typical US numbers, it seems very unlikely that a lane could be more productively used as a busway than as a regular freeway or expressway lane. 



Jack  

www.urbantransport.org <http://www.urbantransport.org/>  







Jack
www.urbantransport.org <http://www.urbantransport.org/>  

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