Jessica, I am not sure how is your background with any of these software but I would like to clarify a little some concepts to help you to make the right choice for your project.
3D Max can do almost everything the only drawback ( if we can call it that way) is rendering time. Since 3D Max uses Raytracing render engines. Rendering animation would be a long process, for that, you'll need more than one machine or a long time to process your frames, this will also depend on how long your animation is and what render engine you are using. This is a typical workflow and we all deal with it.
In the recent years, real-time software had jumped into the stage, software such Lumion, Twinmotion and others that died trying 😛
Lumion and Twinmotion they were designed originally for Architects or similar professionals. The idea was to leverage real-time tools that would let you do things that it will take way longer with 'traditional' ray tracing software. Quality is not the same but is getting better.
Twinmotion and Lumion are turnkey software, you can do a lot but no many customizations, but that's what makes them a good choice when deadlines are tight and quality is not that important.
Beyond that, we have Fully developed Game Engines such as Unreal, Unity, Crysis, and others.
Now here you have to build everything and import animation or create them inside this engine.
Do not think that because you can place easily animate cars in Twinmotion would be able to do the same inside Unreal.
For car animations, you need to import them from other software or create a tool, script, coding inside Unreal to run the simulations.
The learning curve of Unreal is way steper than Twinmotion or Lumion, is just like learning 3D Max, but with a different set of mind, Unreal or any game engine is all about optimisation, where 3D Max as long you have lots of RAM and powerful machines you'll be fine.
If you have traffic simulations done in infraworks, you can export those to Unreal. You can use FBX, that's the formats that Unreal works with, actually is a great format, you'll keep textures, basic materials, animations and more.
If your software can export an FBX, Unreal will be able to open it. Now like with everything nothing is easy or a simple click of a button, the process is complex and require time.
If you have no experience in any of these tool, I would strongly recomend to try Lumion, or Twinmotion. You can do more than nice houses or isolated buildings, Lumion can work with very large projects too. Actually, it has an option to load cities from Open Map, basic buildings and streets.
I don't work for Lumion or Twinmotion team :), actually, I barely use them, most of what I do is 3D Max and VRay, Unreal, but this doesn't mean I don't recognise the power of those tools.
Hopefully, this clears things up a little.
Forgot, to add a sample of Traffic plugin for 3D Max, This was done years back, by the end you can see the traffic-stopping on red lights or stop sign, that you can setup.
https://vimeo.com/220433929
This other video I just did it to test an option to avoid objects, here you can see how the system (cars) avoid the 'Drunken' Walker, pretty cool.
https://vimeo.com/51538608
Best luck.
