Yes, if the induced demand results in similar levels of congestion - which it very often does - there would be more emissions in the end.

And you’re right, cars will exist for the forseeable future. I do not however want the government subsidizing car dependency since it is destructive to the environment and to everyone’s health and safety.

A couple of possibilities to drastically reduce traffic:

• turn all multi-lane streets within cities into single-lane streets for cars with exclusive bus and bike lanes to treat all forms of traffic equally
• reduce all inner-city speed limits to 30 km/h to reduce car noise, emissions and increase pedestrian safety
• traffic lights should prefer public transit, pedestrians and bicyclists instead of cars
• stop subsidizing parking spaces for cars with city money and drastically reduce on-street parking as cars take away massive amounts of space
• put toll roads onto highways as their cost is massively higher compared to fuel taxes. After all, trains have to pay a costly fee to use train tracks already - why should cars have this privilege?

There’s a lot more I could write here but you get the gist. Making car traffic more efficient does not reduce emissions in the long term in the slightest. Making car traffic less efficient reduces emissions instead because people will not use cars as frequently.

And keep in mind, I’m not talking about Bumfuck Nowhere (population: 725) when mentioning public transit. Cities have insane amounts of car traffic which can be massively reduced with just a couple of decisions. This would make car traffic less efficient as right now it enjoys many privileges over other forms of transportation.