Microscopic Traffic Simulation Model
CORSIM includes both NETSIM (for surface street simulation) and FRESIM (for freeway simulation). Version 6 of CORSIM offers the following new features:
Simulation Logic: CORSIM now offers improved simulation logic for lane changing, spillback checking, diagonal movements, complex intersection modeling, freeway acceleration lanes, deceleration lanes, ramp meters, car-following, origin-destination modeling, and setting goal lanes. An enhanced random number generator will produce better distributions, for improved stochastic modeling. Actuated controller parameters may now vary from time period to time period to simulate different time-of-day plans. The number of actuated controllers is now dynamic and limited only by the number of nodes in the network. Signal pre-emption and traffic assignment are now available for actuated signals.
High Occupancy Toll (HOT) Lanes: CORSIM supports different HOT lane pricing algorithms, monetary value of time for each vehicle type, HOT pricing output data, and specification of vehicle types permitted to use HOT lanes in each time period. In addition, the user can specify a percentage of transponders for each vehicle type, and numerous calibration parameters to customize vehicle behaviors near HOT lanes. Sample input files for HOT lanes are automatically installed to the "TSIS Projects" folder.
Advanced Toll Plazas. CORSIM now supports different types of toll payment in each lane, vehicle type restrictions in each lane, and the percentage of vehicles using each payment type. In addition, the toll plazas now allow all settings to vary between time periods, and numerous calibration parameters to customize vehicle behaviors near toll plazas. Sample input files for advanced toll plazas are automatically installed to the "TSIS Projects" folder.
Two-Lane Rural Highways with Passing and No-Passing Zones: Added the ability to pass a vehicle by temporarily moving into the opposing traffic stream on a two-lane highway. Sample input files for two-lane highways are automatically installed to the "TSIS Projects" folder.
Emergency Vehicles: Emergency vehicles (EV) can now be simulated, and can cause signal pre-emption if desired. EV sample data files and EV documentation are now included in the installation.
Vehicle Type Origin-Destination (O-D) Volumes: Previous versions of CORSIM allowed vehicle type multipliers for standard off-ramp volumes, but automatically applied O-D volumes to all vehicle types. CORSIM now also offers specification of unique O-D volumes for each vehicle type. The original O-D inputs are still available for cases in which O-D volumes are the same for each vehicle type.
Modeling Options: 1) CORSIM can now simulate up to eleven through lanes in one direction on a mainline freeway link, i. e. 5 through lanes plus 6 full auxiliary lanes. 2) The minimum desired free-flow speed on surface streets has been reduced to one mile per hour, to approximate vehicles dwelling in locations such as airport passenger pickup zones. 3) Truck lane logic was modified to provide exclusive truck lanes in which non-truck vehicles are prohibited. 4) Sign control can now be active in one time period and removed in the next time period, or vice versa. 5) NETSIM can now simulate up to 9 lanes per intersection approach, up to 3 lanes per turn pocket, and turn pockets as long as 9999 feet. 6) CORSIM and TRAFVU can now handle left-hand drive networks, with TSIS Next as the suggested input editor for using left-hand drive. 7) CORSIM now allows the user to specify the percentage of advanced technology vehicles in the traffic stream, plus car-following time headways for each adaptive cruise control driver type. 8) Auxiliary lanes can now be included on FRESIM interface links.
Click here to view the features that were introduced within CORSIM 5.1.
Microscopic Traffic Simulation Model
Version 5.0 of CORSIM offers the following new features:
Freeway HOV Operations. This feature, which was introduced in Version 4.32, has been finalized. Included are new inputs to specify what percentage of HOVs will use the HOV facility (Record Types 33 and 70) and a new input to specify where HOV vehicles begin to react to an off-ramp (Record Type 20). HOV lanes are now allowed on interface links.
Control Delay MOE. This MOE was added for surface-street intersections and can be used to calculate the Level of Service of an intersection or intersection approach using the HCM method.
NETSIM Vehicle Type Specific Multipliers for Surface Street Turn Movements. This is the NETSIM equivalent of the FRESIM feature introduced in version 4.32. It allows users to apply different turn percentages to different vehicle types, such as trucks. NETSIM and FRESIM both use Record Type 24 for this feature.
In addition to these new features, CORSIM 5.0 includes enhancements and fixes to previously identified problems such as:
Record Type 147 can now be used in FRESIM to specify the distribution of free flow speed based on driver type. It previously could only be used in NETSIM.
Detectors are now allowed on interface links.
Any configuration involving stop sign control can be modeled. Previously, some configurations involving stop sign control were not modeled correctly. Logic was also improved to model configurations involving both stop sign and yield sign control.
The probability of joining spillback, entered on Record Type 141, now also applies to left turning vehicles. It previously applied to through vehicles only.
The maximum number of FRESIM detectors was increased from 300 to 600. The maximum number of FRESIM detector stations was increased from 70 to 200.
Many existing features were significantly improved. Errors in FRESIM collision avoidance, destination assignment and leader determination were eliminated. Changes were made to the logic that deals with vehicles crossing interface nodes to improve the car following between networks. Errors in processing truck restriction lanes were corrected. An error in the way vehicle counts on Record Type 53 were converted into entry volumes was corrected.
FRESIM uses an iterative process to solve a set of equations to assign origin-destination percentages based on inputs from Record Types 25, 26 and 74. Record Type 74 now includes an input for overriding the default value of the criteria for determining that the solution of the gravity model has been reached.
Finally, the following items were changed from version 4.32:
FRESIM Record Type 24 was modified. The specified link must be a mainline link. In version 4.32 the specified link was an off-ramp link. This was done to make it more compatible with the way it is used in a NETSIM network.
The change to the NETSIM lane channelization code zero that was introduced in CORSIM 4.32 was removed. A blank or zero channelization works as it did in version 4.2 and earlier.