Synchro is the better fit for signal timing and standard intersection or corridor analysis based on Highway Capacity Manual (HCM) methods. Vissim is the better fit when congestion, queue spillback, closely spaced intersections or unusual geometry decide whether a design works. Most land development projects start with Synchro and move to Vissim only when the site, the jurisdiction or the traffic conditions call for it. Below, we compare the two on method, data, cost and fit, so you know what to ask your traffic engineer before a study is scoped.
TL;DR
- Synchro is an HCM-based deterministic and signal-optimization tool. Vissim is a microscopic simulation tool. The first is faster to build, the second shows more behavior.
- Vissim handles oversaturated conditions and queue spillback better. Synchro is limited there, according to TxDOT guidance.
- Vissim needs more input data and more calibration. Expect more engineering hours, which affects your study budget.
- Vissim licensing is quote-based. Check the owner of the study: the reviewing agency often dictates which tool it accepts.
- As a landowner or developer you rarely pick the software yourself. You pick the scope, and the jurisdiction's requirements set the tool.
Table of Contents
- What Synchro and Vissim actually are
- Synchro vs Vissim at a glance
- How they differ on congestion and queue spillback
- Signal timing workflows
- Data needs and learning curve
- Is Synchro or Vissim free? Licensing in the U.S.
- How to choose: a decision guide for developers and landowners
- Perspective
- Where Urban Planning Pros fits
- FAQ
- Sources
What Synchro and Vissim actually are
The two programs answer different questions, so the "versus" in the search is a little misleading.
Synchro is a macroscopic, deterministic tool. Wisconsin DOT lists Synchro 12 as an HCM-based deterministic and signal-optimization tool from Trafficware, a CUBIC company. Cubic describes Synchro Studio as combining deterministic modeling with SimTraffic microscopic simulation and animation to model intersections and optimize signals, corridors and networks. Cubic announced that Synchro Studio 12 supports the HCM 7th Edition methodology as of May 2023.
PTV Vissim is a different kind of model. PTV describes it as microscopic, multimodal traffic simulation software that helps planners, engineers and consultants plan, test and justify mobility measures. Each vehicle is simulated individually, with its own behavior, rather than being represented by averaged flows.
Texas DOT states the classification plainly: Synchro is HCM-based (mesoscopic) and Vissim is microsimulation (microscopic). Both are accepted for signalized and stop-controlled intersection analyses, as TxDOT's operational performance guidance shows.
Synchro also includes SimTraffic, which animates the results. That is why some engineers call Synchro a simulation tool. For decisions about queues and spillback, though, SimTraffic is not a substitute for a calibrated Vissim model, as the next sections show.
Synchro vs Vissim at a glance
| Criterion | Synchro (with SimTraffic) | PTV Vissim |
|---|---|---|
| Modeling method | HCM-based, deterministic, with signal optimization | Microscopic simulation of individual vehicles |
| Best known for | Signal timing, intersection and corridor delay | Complex geometry, congestion, multimodal behavior |
| Oversaturated conditions | Limited, especially with spillback | Evaluates them well |
| Non-standard phasing | Limited (for example, diverging diamond ramp terminals) | Suited to it |
| Input effort | Geometry, turning volumes, speeds, peak-hour factor, control type | The same, plus routes, conflict rules, vehicle inputs and optional driver behavior parameters |
| Setup time | Shorter | Longer, with calibration |
| Licensing | Commercial license through Trafficware/Cubic | Quote-based: single-user, floating or cloud subscription |
The rest of this article explains each row.
How they differ on congestion and queue spillback
This is the difference that most often changes a project's outcome.
TxDOT's guidance says Vissim evaluates oversaturated conditions well compared with deterministic or HCM-based tools, and that Synchro is limited in evaluating oversaturated interchanges where queue spillback affects upstream and downstream operations.
Why that matters for a site: a new driveway, a new signal or a new ramp terminal close to another intersection can send queues back into the neighbor. A tool that treats each intersection mostly on its own can report acceptable delay while the real street blocks. A Synchro training article shows how a single setting works in practice: with its blocking option set to "No", vehicles cannot enter the intersection if the downstream queue spills back, and the analyst has to choose that setting deliberately.
Wisconsin DOT's diverging diamond interchange (DDI) guidance goes further. It recommends microsimulation for DDI analysis and cautions that Synchro results may be misleading when nearby intersections and decision points affect operations. The same document notes that Synchro has limits with non-standard signal phasing and cannot easily model driver anticipation, lane utilization imbalances or complex weaving and merging.
The rule of thumb:
- Isolated or evenly spaced signals, moderate volumes, standard phasing: Synchro is usually enough.
- Closely spaced intersections, interchanges, weaving, or volumes near capacity: ask whether the reviewing agency expects Vissim.
- Unconventional designs such as DDIs or roundabout-signal combinations: plan for microsimulation.
Signal timing workflows
Synchro's strength is the timing workflow. Engineers build the network, optimize cycle length, splits and offsets, and review the result across a corridor. One published study in Koya University's journal found that optimizing cycle length in Synchro reduced average delay by 30 to 35 percent in off-peak and PM peak hours. That is one study of one network, not a promise for your site, but it shows why Synchro remains the everyday tool for timing plans.
Vissim is usually not where timing is born. TxDOT's microsimulation guidance says it is best practice to import an RBC signal file from Synchro as a baseline and check its timing in Vissim, because values are sometimes not imported correctly. In practice the two tools often work together: Synchro to develop and optimize the timing, Vissim to test it under real queue behavior.
On quality of optimized timing alone, the gap can be small. A study of a real arterial with 12 signalized intersections found that Vissim-based genetic algorithm optimization and Synchro produced the highest-quality signal timing, with extremely similar performance. The extra effort of Vissim pays off in what it shows about behavior, not automatically in a better timing plan.
Data needs and learning curve
Both tools start from the same base. TxDOT lists what Synchro needs: geometry, turning volumes, speeds, peak-hour factor and control type. Vissim needs those plus routes, conflict rules, vehicle inputs and signal timing, with driver behavior parameters as an option.
Two consequences for a developer:
- Field data matters more with Vissim. PTV says accuracy depends on sound geometry, demand inputs and calibration with field data. Counts, observed queues and travel times collected early save rework later.
- Geometry quality shows up in the result. A good base drawing is the cheapest input to improve. Our topographic survey and existing-conditions work gives traffic engineers accurate edge-of-pavement, driveway and lane information to build from.
On learning, Synchro can be picked up faster. Vissim takes longer to build and calibrate, and its training is a real cost: PTV's calendar lists a North America online course at US$1,400 on its 2026 to 2027 schedule. Check that page for current dates and prices.
One more detail worth knowing: neither tool outputs equivalent through-travel time (ETT) directly. TxDOT notes that Vissim can account for it by setting up travel-time routes.
Is Synchro or Vissim free? Licensing in the U.S.
Neither is free for commercial work.
Vissim. PTV says commercial licenses are quote-based, and academic users may apply for a free Thesis License. Licensing can be single-user, floating (on-premise) or a cloud-connected subscription through PTV Hub. Pricing is tailored to project scope, network size, required modules and licensing setup. The packages are Junction, Corridor and Advanced for different network sizes, plus Automotive for ADAS and automated driving.
Synchro. Trafficware sells Synchro Studio through its sales channel, and we do not quote list prices here because they change by version and license type. Ask the vendor or your engineer for current terms.
For a landowner, this is mostly background. The software cost sits inside your engineer's fee. What you control is whether the scope calls for the heavier tool.
How to choose: a decision guide for developers and landowners
You will rarely run either program yourself. The useful question is: which analysis does my project need, and who decides?
Start with the reviewing agency. Wisconsin DOT, for example, tells engineers to use its TEOpS 16-10 supported tools list to select software for project-specific analyses and to consult the regional traffic engineer before changing tools or versions. Texas publishes its own guidance. Your city, county or state DOT will have an equivalent expectation, and it varies by jurisdiction. Confirm it in writing before the study is scoped.
Then match the tool to the conditions:
| Project condition | Likely tool |
|---|---|
| Single site, one or two signalized intersections, standard phasing | Synchro |
| Corridor retiming or signal coordination | Synchro, possibly with SimTraffic |
| Driveway near an existing signal with known queues | Synchro first, Vissim if spillback is visible in the field |
| Interchange ramp terminals, close spacing, heavy weaving | Vissim |
| Non-standard designs (for example, DDIs) | Vissim |
| Public presentation needing animation of vehicle behavior | Vissim, or SimTraffic for a simpler view |
If you are unsure, the cheapest protection is a scoping conversation before the traffic engineer starts. Ask three questions:
- Which tool does the reviewing agency require or prefer for this project type?
- Are queues from nearby intersections already reaching the site?
- Will the study need to hold up through a contested approval or a hearing?
Our guide to the traffic impact analysis process for developers shows where this software choice fits in the full study. If your question is whether a new signal is even justified, start with a signal warrant study before modeling either way.
Perspective
Most of the software debates we see start too late. A team argues over Synchro or Vissim after the site is under contract, when the real question was whether the site's access, frontage and surrounding intersections would support the project at all.
Our view is that the tool follows the risk. If a site's access depends on a signal near a congested intersection, we want the traffic engineer to know that during feasibility, not during permitting. That is why we gather property documents, zoning constraints and survey data first, and coordinate the engineers who will run the analysis around what the evidence shows.
We do not treat software as the deliverable. The deliverable is a decision: buy, sell, redesign or proceed. A simple Synchro model that answers the jurisdiction's question is better than a Vissim model built for its own sake, and a Vissim model is worth its cost when spillback could sink an approval. Our approach is designed to put that judgment in front of the owner early.
Jeremy Wenger
Where Urban Planning Pros fits
We do not sell traffic software, and we do not replace your traffic engineer. We help owners and developers settle the questions that decide whether a traffic study is simple or expensive: site constraints, access, jurisdiction requirements and the engineering scope.
Our feasibility studies evaluate property documents, zoning and infrastructure before you commit capital. Our survey and engineering coordination provides accurate base geometry for whichever model your engineer builds, and our concept site and utility plan work tests how access will lay out.
If you are scoping a project and are unsure which level of traffic analysis the jurisdiction will expect, book a feasibility call through our services page. We will help you define the scope before it becomes a cost.
FAQ
Is Vissim better than Synchro?
Neither is better in every case. Vissim is stronger for oversaturated conditions, queue spillback and complex geometry. Synchro is stronger for fast signal timing and standard HCM-based intersection analysis. The better choice depends on the project and on what the reviewing agency accepts.
Is Vissim software free?
Not for commercial use. PTV quotes commercial licenses individually, and academic users may apply for a free Thesis License. Licensing can be single-user, floating or cloud subscription, and the price depends on modules and network size.
What type of software is Synchro?
Synchro is a traffic signal timing and intersection analysis program built on HCM-based deterministic methods. It includes SimTraffic, a microscopic simulation and animation component. Wisconsin DOT lists it as an HCM-based deterministic and signal-optimization tool.
Can you use Synchro and Vissim together?
Yes, and it is common. Engineers often develop signal timing in Synchro, export it, and then check it inside Vissim. TxDOT recommends verifying imported timing in Vissim because some values do not always transfer correctly.
Which one does my project need?
Ask the reviewing agency first. For a simple site with standard signals, Synchro often meets the requirement. For interchanges, closely spaced signals or heavy queues, expect the agency or your engineer to call for microsimulation.
Sources
- Traffic Analysis Supported Tools, Wisconsin DOT
- Synchro Studio, Cubic
- Cubic Upgrades Synchro Studio, Business Wire
- PTV Vissim, PTV Group
- TxDOT 11.3.6 Additional Operational Analysis
- TxDOT 10.3.4 Stage 2 Operational Performance and ICE
- TxDOT 13.4 Base Model Development
- Best Practices of Diverging Diamond Interchanges, Wisconsin DOT
- Modeling Traffic Operations in Synchro/SimTraffic, Part III
- Synchro software-based alternatives for improving traffic, Koya University
- Cross-Evaluation of Signal Timing Optimized by Various Methods
- PTV Vissim FAQs
- PTV Vissim Pricing and Licensing
- PTV Training Calendar