[sustran] Re: Article in Guardian Newspaper

[Jack Mallinckrodt]

At 12:42 AM 3/30/03, Alan Patrick Howes wrote:
>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.

JM: Agreed and as I said. Still, there are many that argue that IN GENERAL 
( that means averages) bus or rail is a more efficient use of land, ROW, 
and public funds.  The averages numbers show that's terribly wrong.

>
>Bus lanes don't get put in "average" locations, they get put where bus 
>loads are heaviest - or they should do.

As do road lanes.


>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!


Yes it is.  Perhaps I was remiss in not saying so, but it should be clear 
that so also, is the 231 bus/hour result. As such it's an apples to apples 
comparison.  Still, for the case of US average conditions, 231 buses per 
PEAK hour along a given route is hard to imagine, although I've seen, and 
counted more than that ( in each of two bus lanes in each direction !) in 
Santiago, Chile.

Jack

========
>
>
>--
>Alan P Howes, Special Transport Advisor,
>      Dubai Municipality Public Transport Department
>aphowes at dm.gov.ae
><http://www.dubaipublictransport.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 
>>(<http://www.urbantransport.org>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/>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
>><http://www.urbantransport.org/>www.urbantransport.org
>
>Jack
>www.urbantransport.org

Jack
www.urbantransport.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://list.jca.apc.org/manage/private/sustran-discuss/attachments/20030330/2a583957/attachment.htm