Technical Details:

1. The Basic Model Framework
• Traffic is considered at the level of individual vehicles;
• Individual vehicles' movements are simulated at every one second, according to:
• Car-following models, lane-changing models and gap-acceptance models;
• Vehicle follow fixed routes from their origins to destinations;
• 6 vehicle types are currently modelled: car, bus, guided-bus, taxi (HOV), LGV and HGV;
• Individual vehicle characteristics:
  1. vehicle type;
  2. vehicle length;
  3. driver's reaction time;
  4. minimum safety headway;
  5. normal and maximum acceleration;
  6. normal and maximum deceleration;
  7. desired speed as a factor of "standard" link speeds;
  8. acceptable gap
2. Network Representation
• Junctions : priority, signalised, roundabouts, signalised roundabouts, merge, and dummy;
• Links: two-way, one-way, guideway, rural two-lane roads without double-white lines (i.e. overtaking may take place on road space in the direction of opposing traffic);
• Lanes: turning restriction, access restriction (e.g. bus lane, HOV lane), lane closure partially or fully in space and time;
• Detectors: selective vehicle detector;
• Bus stops: ordinary bus stop or bus layby.
3. Public Transport Simulation
• PT service (bus, guided bus);
• Service routes and bus stops;
• Two types of bus stops: ordinary bus stops and bus laybys;
• Bus dwell time in response to passenger flow;
• Reserved bus lane with setbacks;
• Guideway for guided bus.
4. Selective Vehicle Detection and Responsive Signal Control
• Selective vehicle detection;
• Journey time prediction (from the detector to the stopline);
• Signal priority measures:
1. extension of bus green signal;
2. early termination of bus red signal;
3. demand-dependent signal phase;
4. plan selection;
5. equi-saturation policy.
5. Automatic Speed Control
• "Electronic traffic calming" where only the speeds exceeding the speed limits are controlled;
• Externally-defined speed limits can vary from link to link, and even within a link to represent, say, different speed limit for a sharp bend on the road;
• Levels of driver compliance or system penetration.
6. Road Pricing
• "Congestion Metering" as proposed for Cambridge, where a charge is levied if the travel time over a certain distance (such as 0.5km) road exceeds a threshold time (such as 10 minutes);
• Variable charge levels according to the time exceeding the threshold;
• Time-based charging;
• Distance-based charging;
• (Cordon-based charging).
7. Pollution and Energy Modelling
• Emissions from pollutant CO, NOx, and HC;
• Fuel consumption;
• Calculation takes into account of vehicles' acceleration, deceleration, idling and crusing.
8. Outputs
• On-line animation of the traffic movements;
• Individual vehicles' space-time trajectories;
• Statistical measures of:
1. queue length;
2. flow and flow variation;
3. delay and delay variation;
4. speed and speed variation;
5. pollution emission; and
6. fuel consumption at regular output time interval, for each type of vehicles, each link, each route, and the whole network.
7. Speed distribution (by road types in terms of speed control limits);
8. Detector measures: flow, speed and speed variation.
9. Link with assignment models
• Link with the DRACULA day-to-day model of:
1. route choice;
2. departure time choice; and
3. drivers' network learning process from day-to-day.
• Link with SATURN: use SATURN networks and its equilibrium assignment.