This software review evaluated Paramics and Vissim from two perspectives:
To assess the first perspective, we coded the network and timed how long each coding task took. The second perspective was measured by actually timing the simulation speed using the same computer.
Study Area and Network Details
The study area we modelled was a 2.5 mile section of Interstate 5 in Southern California. The exact location is between south of the Avenida Vista Hermosa overpass and north of the Camino De Estrella overpass, as shown in the image below. This study area includes:
Map of the study area I-5 in southern California
Network Coding Time
The fundamental details of model development, as shown in Table below, are prepared before the development of the models.
|Background image||Obtained from Google Earth|
|Vehicle Type||SOV, HOV, Truck, Bus|
|Road Facilities||65 mph for freeway and 45 mph for arterials and ramps|
|Number of Zones||7|
|Demands||estimated using traffic data gathered from PeMS (https://pems.eecs.berkeley.edu) and observed turning count data|
Two expert coders were assigned to code the study network under Paramics and Vissim, respectively. Both coders first discussed the coding requirements in both software and then summarized a list of tasks/steps that need to be followed to code a network. It is noted that the actual procedure to code a network in both software may vary.
Then, the coders were asked to recap or re-learn various modules (if needed) before each coding task, which was not counted in the coding time. We only counted the time taken to perform the actual coding tasks.
The tasks to code the network, the technical terms and coding details used by different software, and the time taken for each task are listed below.
|Category||Task||Paramics||Paramics Time (min)||Vissim||Vissim Time (min)|
|Network setup||1||Vehicle type and classes, Road Category, and Simulation time setup||2||Vehicle type and classes, Road speed distributions, Simulation time setup||9|
|Network Coding||2||Load overlay||5||Load overlay||10|
|4||Network Adjustments: curve, kerbs and stoplines||65||Network Adjustments: Add shape points to better match background, reduced speed area||26|
|5||Speed limit (category defines speed limit)||0||Add desired speed areas||12|
Lane attributes (HOV lane restrictions)
|3||Lane closure (HOV lane restrictions)||8|
Movement/Priority (nextlane, barred turns)
|8||Signal Control: 2 fixed-time and 2 ASC, including detectors for signal||30||Signal Control: RBC module for all 4 signals, added controllers, signal heads, detectors, conflict areas, priorities||72|
|9||9. Infrastructure: link based detectors||14||9. Lane based detectors||30|
|Travel Demand & Route Choice||10||Route choice(change configuration)||1||
Add nodes to the network
|11||Add zones||2||Add parking lots and zones||9|
|12||Load Demand: Use Demand editor to add demands, profile, matrix files||4||Load Demand: Manually generate multiple fma files to reflect demand variation using excel and 3rd-party text editor||7|
|Network Fine-tuning and Simulation||13||
13. Network adjustment, local parameters, lane choices
Network adjustment, local parameters, dynamic assignment simulation
|14||Measurement (only collect general data)||1||Evaluation (only collect overall performance)||1|
|15||3D vehicle setup via PMX||2||3D vehicle setup||2|
It should be noted that for a beginner just learning the software, the time it takes for each task will be greatly increased. For example, one of colleague who knows very little about Paramics couldn’t finish coding network in Paramics when other two expert coders coded their networks.
Here are a few notes about these tasks that deserve to be mentioned here:
The final coded network in Paramics can be seen here:
Screenshot of coded network in Paramics
In VISSIM, the coded network is shown below:
Screenshot of coded network in Vissim
Network Coding Time Comparison
Comparing the cumulative network coding time for each task between these two software’s, it was found that the tasks take relatively the same amount of time up to Task 7: Movement/Priority (Paramics) & Link-link connectivity (Vissim). Among tasks 1 through 7, it was found that Paramics takes a shorter amount of time overall to prepare the network then Vissim, Paramics took more than twice as long, compared to Vissim, to modify the network to correctly match the overlay by making curves, kerbs and stopline adjustments.
For Tasks 8 and 9, however,
Graphing the cumulative time spent on each task, we can graphically see how these two software’s compare for each task.
Paramics & Vissim Individual task time comparison
Simulation Time Comparison
After coding networks, we spent some time to roughly calibrate the networks in order for them to be in good shape to be simulated. We didn’t compare the time taken for model calibration. We think some additional work is still needed to make models to be in better shape. For example, Paramics network is a little bit more congested than the Vissim network. One possible reason is that Vissim removed stuck vehicles but Paramics does not (the vehicle removal tool of Paramics can remove stuck vehicles during model development phase but it is not suggested being used during model production runs).
The same computer was used to simulate Paramics and Vissim simulation models. The computer has an Intel i7 920 CPU running at 2.67 GHz. It had 8GB of RAM and a Nvidia Geforce 9800 GTX+ video card. The operating system was Windows Vista 64 Home Premium Service pack 2. During simulation runs, all cores of CPU are used to maximize the simulation speed.
The times taken to simulate Paramics and Vissim networks are shown in the graph below. We can see the actual simulation time is comparable for the simulation runs without displaying vehicles. However, when we rdisplay vehicles during simulation, Vissim takes much longer time compared to Paramics. This difference is most likely attributed to Paramics utilizing video card’s hardware acceleration (i.e. OpenGL).
Paramics and Vissim Simulation calculation time
In summary VISSIM and Paramics both provide benefits and drawbacks. A more refined comparison will be conducted to tell you more about them.
PTV America sent us an email on 11/6/2012, saying that Vissim 6.0 or higher has much faster simulation speed with vehicle visualization. However, we didn’t have the version of the software and thus won’t be able to provide an update on how fast the simulation is under V6. Also, PTV America mentioned that V5 modelers need to avoid using the Aero theme.