Passes Ankdamsrondellen in a tunnel underneath??
Tvärbanan Frösundaleden cost reduction Minimise Construction works Trains to cross Ankdamsrondellen at grade Suggested to cross also Solnavägen at grade instead of grade separated in tunnel
Tvärbanan-Light Rail compared with Trams Tracks (often) segregated from the carriageway Higher Capacity and speed then Trams Absolute priority at signalised junctions
Ankdamsrondellen Early attempt at design – all arms signalised
Absolute priority for the light rail train The train needs a green light at least 150 meters before the junction The driver must decelerate to 15 Km/h at a point at least 40 m before the junction The train needs at least 32 seconds to cross the junciton. At best, an extension of an existing phase of 21 seconds At worst, 53 seconds is needed if two trains meet This results in long red times for movements that are in conflict with the train!
How will the traffic on Frösundaleden be effected? Can the train be given absolute priority through Ankdams roundabout? What will be the delay for conflicting traffic flows and will those delays affect the operation of adjacent junctions? Will the project affect the traffic flows for the whole area?
Methodology To answer these questions we decided: To model the network for two future years; 2007 and 2015, using the software Sampers and EMME/2. The mesoscopic model Dynameq was used to evaluate the effect on the Solna network. LINSIG was used to find a working layout for the junction and traffic signal designs and to get co-ordinated signal timings for Dynameq and Vissim. To use a microsimulation model (vissim) to evaluate the final design. Expanded microsimulation model to evaluate the effects of bus priority on Frösundaleden
DYNAMEQ Mesoscopic model DYNAMEQ Network for Stockholm and Solna
DYNAMEQ The graphical user interface for traffic Signals in DYNAMEQ Staging Intergreen times Green times
LINSIG Brittish traffic signals model Models isolated junctions and networks Can model signalised roundabouts Can model several signal cycles Junction coordination
Work flow SAMPERS/ EMME/2 Distribution of traffic on the Dynameq network Use traffic flows from DYNAMEQ…..to optimize the signals network in LINSIG Put the signal timings back into DYNAMEQ To get the final traffic flows on the network LinSig optimised one last time
DYNAMEQ Network 2015 With train Traffic flow on Gränsgatan halved during peak hour +200 through Råsunda
Saturation rate at 103% on Frösundaleden!
Vissim Vissim was used to evaluate the designs
Conclusions The different models complement each other: Dynameq good for traffic assignment. Linsig good for co-ordinated signal timings. Vissim good for evuation of the detailed design. The effects of our design descisions quickly become apparant easing the descision making process. However, any change in the design means you have to update at least two different models. We havent found any one model that can handle all levels of modeling as well as traffic signal optimisation.