I've never used the Nraas mods "Overwatch" and "traffic". I believe together, these mods prevent inactive sims being assigned cars in their inventory to get around, deleting excess cars in the world and instead making cars without owned cars get taxis or walk. However, are these actions performed automatically by the mods or must you select options with the mods in the game? I have not played the sims 3 in years, so I need my knowledge brushing up seriously.

I don't know anything about Traffic, but I do know that with Overwatch, excess vehicles are removed every night by default.

You get a number of options with Nraas Traffic, which you must set yourself by clicking on the City Hall rabbithole, selecting Nraas and then Nraas Traffic. You can set the number of Food Trucks and Ice Cream vans in the town and control which lots they can call at and when: (a very useful feature since I hate having that ice cream van parked outside my house half the day!). You can control whether or not sims lacking vehicles of their own will use taxis, allow or disallow vehicles during general routing, and disallow the use of career limousines. The feature I find most useful is Traffic Delta: it limits the number of vehicles generated by the game. I usually set it to something like -500, which has the effect of limiting the number of taxis buzzing around town, most of which are 'ghost' taxis which nobody is actually using.

The NRaas Traffic setting to disallow the automatic issue of free, cheap cars that the inactives then tend to abandon is on by default. But this is a good mod on which to check out the options (on City Hall) since there aren't an overwhelming number of them to take in all at once like some of our other mods. The performance career limo one does need to be set and that's often the one that due to an EA programming glitch leads to an absurd number, like in the thousands or tens of thousands, of limos being issued that the player cannot see but that can choke the game and cause Overwatch to have heartburn when it has to clean up the otherwise invisible mess every night.

The Traffic Delta setting is great to mess with too, but as stated that one controls the fake (no driver, no passenger) ambient taxis that the player sees and that can look really out of place in non-urban worlds.

@igazor Wow! I didn't know that about the performance career limos. It might possibly explain the thousands of mystery vehicles that Overwatch was deleting at one point. Well, I shall certainly be using that feature from now on.

I understand how it would be used now, thank you.