Sure, we can absolutely have both, we should just be preferring mass transit to personal transit for populated areas.

In my area, we have:

• one major corridor with a big highway (5+ lanes) and a commuter train line
• a light rail system in the urban area, with some branches extending to the suburbs
• old freight rail line that connects to the existing light rail system and passes through several suburban areas, but doesn't have light rail service
• long stretches of "nothing" (~50 miles) to smaller metro areas, and after a few hundred miles goes to a popular tourist destination

We've been having more traffic recently, so what's the state-wide transportation system's decision? Delay expansion of rail and expand the highway.

What we should instead be doing is:

1. extend light rail through existing rail line through busy corridor - great alternative to the commuter rail since it goes different places
2. increase housing density along rail lines through zoning changes, and mix in commercial zoning w/ residential
3. improve cycling and pedestrian infrastructure with a focus on connecting to rail infrastructure
4. reroute cars to make it less convenient to get around in the city by car - i.e. nudge people toward using transit instead of personal vehicles

Transit will never fully replace personal vehicles, but it can drastically reduce the need for driving within urban and suburban areas. Rail lines are a lot cheaper to maintain than roads, and trains can carry a lot more people than cars. In other words, if we can get people to use trains more than cars, we can reduce our spending on transportation infrastructure.

We should absolutely keep and improve our existing highway infrastructure, but we should also be phasing out a lot of our road infrastructure in densely populated areas in favor of mass transit options that move people more efficiently.