The problems caused by large roads cannot be solved by making those roads larger. I am often frustrated by planners and elected officials who insist on spending scarce resources on a pretend solution such as a freeway expansion or bypass road. Their logic is that reducing traffic congestion will necessarily improve air quality by reducing idling, which causes the most harmful emissions. Yet such initiatives don't accomplish anything except creating jobs for road construction workers (who, by the way, seem to hate motorists because careless drivers regularly kill their colleagues).
Roads and highways are part of a system. You can make a highway segment as wide as you want, but once it narrows there will be a bottleneck, and you cannot eliminate anywhere near all the bottlenecks. By widening a segment your best hope is to move the congestion a little further down the highway.
If you built it, they will come. New road capacity is very quickly filled up as the "improvement" created an option for people to drive further or to a different place. Now those people are stuck in traffic and regretting their life changes. We cannot build our way out of traffic congestion with more and wider roads.
Air quality does not improve. If you induce more car traffic, the air and noise pollution and all associated dangers will continue to rise. Is should be unacceptable to use Congestion Mitigation and Air Quality (CMAQ) funds for any road project except a road diet.
Transit continues to suffer. I can't count the number of times I've seen buses used as a pawn to win support for anti-transit projects (or opposition to pro-transit projects). Traffic engineers like to claim that if a project makes things better for all traffic then it's an improvement for buses. Don't fall for this lie! Road expansion projects induce driving, thereby increasing bus delays and making buses less attractive. If you want to improve bus service on congested roadways, the only answer is a dedicated bus lane.
The only way to reverse congestion is to invest in sustainable transportation options such as walkways, bikeways and high quality transit services. Instead of spending millions adding new asphalt, dedicate an existing lanes to buses and invest that money in new bus routes to meet the demand served by the highway. Give people real options and make it easy to use them, and they will come.
P.S. No podcast episode this week due to the American holidays but my voice will return next week.