340 likes | 430 Views
The importance of interactions in determining service measures for bicycles. Chris Osowski chris.osowski@soton.ac.uk – www.osowski.co.uk Institute for Complex Systems Science, University of Southampton
E N D
The importance of interactions in determining service measures for bicycles Chris Osowskichris.osowski@soton.ac.uk – www.osowski.co.ukInstitute for Complex Systems Science, University of Southampton Ben Watersonb.j.waterson@soton.ac.ukTransportation Research Group, University of Southampton
Is this good? From: Warrington Cycle Campaign “Cycle Facility of the Month” (http://goo.gl/EiBnDv)
Are these value for money? From: Warrington Cycle Campaign “Cycle Facility of the Month” (http://goo.gl/EiBnDv)
Capacity of Motor Infrastructure From: Transportation Research Board. (2010). Highway Capacity Manual.
Capacity of Motor Infrastructure From: www.flownz.com
Capacity of Pedestrian Infrastructure From: Colin Buchanan Ltd. (2010) From: Fruin, J. J. (1971). Pedestrian Planning and Design From: Halcrow Group Ltd. (2005)
Capacity of CycleInfrastructure From: Navin, F. P. D. (1994). Bicycle Traffic Flow Characteristics: Experimental Results and Comparisons. ITE Journal, (March), 31–36.
A Quote from Fruin… “[...] many authorities are using maximum capacity ratings for dimensioning pedestrian space. No evaluation or consideration of human convenience has been made in developing these design standards. The flow curves [... demonstrate] that the maximum capacity of a pedestrian traffic scheme is attained only when there is a dense crowding of pedestrians.” From: Fruin, J. J. (1971). Pedestrian Planning and Design
What about Quality of Service? • Botma(1995) assumed no impedance; i.e. fixed speed. • Does this matter…? • Can we use simulation tools, take the best practice of the simulation of other modes and cross-apply itto find out?
Use Pedestrian Modelling? From: Colin Buchanan Ltd. (2010) • Often continuous space (2D) models. • Successful tools at variety of scales • Pedroute • Legion • VisWalk • … From: Halcrow Group Ltd. (2005)
The Social Force Model • Helbing, D., & Molnár, P. (1995). Social force model for pedestrian dynamics. Physical Review E, 51(5), 4282–4286. • “Motivation to act”
Our Model – Purpose • Do interactions matter? From: CXMagazine.com
Our Model – Implementation • Agent Based Model • 2 dimensional continuous space • Unidirectional flow • Fixed path width • Parallel boundaries
SFM – Directional Perception • In Helbing and Molnár (2005):
Our Model – Parameters and Outputs • Bicycle behavioural parameters: • Generally from CROW (2007) • Exploratory variables: • Path Width and Bicycle Arrival Rate • Output data: • Average speed, average crashing proportion, average distance to the nearest bicycle, etc.
Results – Speed vs. Flow High Quality Poor Quality Variable Quality
Results – Crashes (No impedance)
Results – Crashes • Flow breakdown with speed-selection occurs primarily as multi-bicycle collisions at the entry: • Without speed-selection:
Conclusions • Lack of robust quantitative measures for capacity or quality of service. • Inherent assumption that service quality is satisfactory up to capacity… …bicycles do not interact in a meaningful way.
Conclusions • 2Dmicrosimulation model using the SFM. • Basic behavioural traits applied. • Data show qualitatively different result... …sudden collapse in quality of service. • Modellingconfirms intuition that we can’t ignore service quality for non-trivial flow rates.
Acknowledgements • EPSRC Doctoral Training Centre grant: EP/G03690X/1 • University of Southampton: • Institute for Complex Systems Simulation www.icss.soton.ac.uk • Transportation Research Group www.trg.soton.ac.uk • IRIDIS High Performance Computing Facility (and support services)
Questions? Paper at: https://db.tt/8APJ8Vrk
Barriers to Cycling • TfGM, 2011
Barriers to Cycling From: City of Copenhagen. (2011). Copenhagen: City of Cyclists - Bicycle Account 2010.