If the Triangle’s population stopped changing and travel demand is frozen solid, then yes, optimized buses would be all that we need today. We actually know that as, due to how the FTA’s standard procedures work, it’s actually hard to argue in our federal grant applications that we have the demand to justify commuter rail for present-day needs.
But also pay attention to what I wrote in italics -and think about how we know that’s not true.
We know for certain that the Triangle is growing, with hundreds of people moving to our area every day. This means traffic congestion is expected to get worse; our roads can handle the gridlock that occur today (below is the average peak-hour congestion as of 2016; it’s obviously worse now)…
…which is showing that many roads are still regularly letting cars flow relatively freely (colored in green). However, if the Triangle grows as we expect it to, we know that our roads will not be able to handle this by 2050:
Even traffic signal priority will not mean anything if there is regular traffic sitting in front of buses. If you want public transit to work better for people (or even just keep working at all), this means bigger infrastructure investments are needed so that transit vehicles can operate in an even more separated way -either with separate lanes (BRT) or separate infrastructure altogether (trains, bikeways etc.).
We also know that 20% of all homes and 45% of all jobs in the Triangle will be located along the future rail corridor. Sure, the flip side of that is that 80% of all homes and 55% of jobs are outside of the corridor. However, that’s spread out over 96% of the Triangle, geographically. This means we could either spread ourselves thin across that much of our region, or we could get away with developing on less than 4% of the land to improve the lives of just as many people.
This means that you could make it easier for so many people to get around in a more cost-effective way by investing in transit.