Insert the title of your presentation here Presented by Name Here Job Title - Date SCOOT MMX (Multi-Modal 2010) Presented by Alan Stevens TRL
TRL David Bretherton (TRL) Helen Gibson (TRL) SIEMENS mobility Peek Traffic Transport for London Kernel Development System Integrators SCOOT Users Mark Bodger (Siemens) Jason Robinson (TfL) Ian Skeoch (Peek)
How SCOOT Works Online Model every second 24/7 loop © Copyright TRL Limited
Page 4 Main new features in SCOOT MMX Pedestrian priority Reduced cycle time at quiet times Cycle time sub-region independence Updated emissions estimates
1 – Pedestrian priority: Variable invitation to cross For sites with high pedestrian demand Four pedestrian priority levels Provides a longer invitation to cross -Cycle time is not increased – longer cycle time would mean pedestrians wait longer -Increase in pedestrian Green is achieved by an increase in saturation, so potentially increases vehicle delay on busiest links of the junction Page 5
Pedestrian priority level Using pedestrian-counting detection By timetable Using time from end of pedestrian green to the first pedestrian push button press Benefits: improved safety where pedestrian demand currently exceeds pedestrian capacity Improved efficiency – at some sites it may be possible to shorten green time to pedestrians when demand is low
2 – Reduced cycle time at quiet times Allows shorter cycle times when a demand dependent stage is rarely called Implemented by reducing selected stage times to zero: “ghost stage” But if there is a flow demand during a ghost stage: -may take a few cycles for normal offset to be restored -resulting in temporary local inefficiency
Benefits of reduced cycle time at quiet times Cost of delay when region cycle is on a minimum estimated to be £53,500 per node per annum on average New facility estimated to allow the region cycle time to be reduced by 10% on average Over the 2300 (current) nodes in London controlled by SCOOT cost savings of £11,500,000 per annum Depends on whether demand dependent stages keep the regional cycle time higher than necessary Benefits estimated using data from London Periods when region cycle time is on a minimum identified
3 – Cycle time sub-region independence There is a trade-off between efficiency of individual nodes (e.g. cycle time) and overall network efficiency. SCOOT keeps all nodes in a region at the same cycle time -Essential for coordination -But some nodes may be operating at cycle times higher than their minimum practical cycle time (MPCY), so are inefficient At quiet times it may be better for a node to operate independently at its MPCY Concept of sub-regions introduced: -Several nodes can become independent together -Always at the same cycle time as each other -Independent cycle time is the highest MPCY of the nodes in the sub-region -Nodes within a sub-region cannot become independent separately Independence can be user-defined or automatic based on comparison of delays Page 9
4 – Emissions Estimates Emissions estimated: -Carbon Monoxide, Hydrocarbons, Oxides of Nitrogen, Particulate Matter, Carbon Dioxide New estimates of : -Total Carbon -Fuel consumption Estimates based on: -Total Flow on each link -Mean speed on each link -Proportion of 7 classes of vehicle -Distance travelled
Summary SCOOT MMX continues multi- modal theme of recent releases New and updated emissions estimates Pedestrian facilities particularly aimed at junctions with high pedestrian demand Improved efficiency in low flow periods through cycle time sub- region independence and the introduction of ‘ghost stages’ so that region cycle time is reduced Future measurement of actual benefits