Andrew Curran from the Greater Vancouver Transportation Authority (TransLink) provides a spreadsheet of potential scenarios that Velib' could create on bike mode share in Paris and encourages its use by others. The spreadsheet is in Excel and available for download. Says Andrew:
"Scenario #1a shows that once Paris is finished installing all 20,600 public bikes, they will have more than doubled their cycling mode share in the span of a few months – increasing by 118% (from 1.63% to 3.55%). This result assumes that each public bike will be used for the current average of 6 trips per day and that there will be no concurrent increase in private cycling trips. It also assumes that 4% of public bike trips will replace private bicycle trips and that 2% of public bike trips would not have been made otherwise. Trips being shifted away from motor vehicles (~7%), walking (~37%), and public transit (~50%) are not factored into this model since they do not affect the overall number of trips being made.
"Experience from Lyon suggests that a significant increase in private cycling trips is likely to occur as well since the public bicycle system acts as a “door opener” to increase the acceptance of cycling as an urban transport mode. If, in addition to the already-realized mode share growth described above, private cycling trips in Paris also increase by 50% (shown in Scenario #3a) - then Paris would achieve a 4.37% bike mode share representing a 168% increase over pre-July levels.
"The remainder of the scenarios (#4-10) show what would happen to mode share if the number of Velib bikes was doubled, the number of trips made per day on Velib bikes was doubled, and the number of trips made by private bicycle increased by 50%, 100%, 200%, and 400%. The final scenario shows that for a 15% mode share to be realized, the number of public bikes would need to be doubled (to 41,200), the number of trips made on each bike per day would need to be doubled (to 12), and the number of trips made by private bicycle would need to increase by 331% - or some combination thereof.
"Playing around with this very basic model (e.g. changing number of public bikes, number of trips, rate of private cycling increase) starts to give a rough sense of the scale of mode share change that could be realized through a public bike system."
Methodology and Data Sources:
· City Population 2006 & 2008 assumes current trend of 0.2% growth per year (http://en.wikipedia.org/wiki/Paris#Demography)
· Trips/Day/Capita of 2.85 is about standard for large cities in Western Europe (p.11 - www.mobility-bovy.ch/pdf/BEIJING_conf.pdf)
· 2006 Bike mode share of 1.63% (p.2 - http://www.jcdecaux.com/UserFiles/File/dossier%20de%20presse%20velib.pdf)
· Recent article in The Economist reports system is clocking about 100,000 rides per day (http://economist.com/business/displaystory.cfm?story_id=9832847&CFID=20091423&CFTOKEN=92202690) equalling roughly 10 trips/day/public bike. I had earlier read that each public bike was averaging only 6 trips per day (http://www.news.com.au/story/0,23599,22181882-1702,00.html)
· Assumption made that 4% of public bike trips are replacing private bike trips and that 2% of public bike trips are new trips that would not have been made otherwise – as was reported from the Lyon experience (http://ange.archangelis.com/typo3/niches/fileadmin/New_folder/Deliverables/D4.3b_5.8_b_PolicyNotes/14397_pn4_public_bikes_ok_low.pdf)
· 2008 Total trips/day calculated by multiplying projected 2008 population by 2.85 and then adding the new 2,016 trips occuring due to the public bike system
· 2008 Private bike trips/day calculated by multiplying projected 2008 population by 1.63% and then subtracting the 4,032 trips that occured instead by public bike
· 2008 Total Bike Trips / Day calculated by adding Private bike trips (96,447) and Public bike trips (100,800) together
· 2008 Bike Mode Share (3.2%) calculated by dividing bike trips by total trips