Because the point of the comparison is to determine if the infrastructure investment was cost effective. What would traffic look like today if the money had instead been used to build public transport, bike lanes, and walkable streets? If the alternative investment had improved traffic even more, building the highway was the wrong thing to do.
A lot of people insist that any highway projects always just induce demand, resulting in even more congestion, but the Big Dig did nothing of the sort. To this day, 30 years on, Boston traffic is still not as bad as it was pre-Big Dig.
Induced traffic does not mean that traffic on a specific place inevitably goes back to what it was before a new highway. It means that total traffic, including old and new infrastructure, always goes up if the total road capacity goes up.
Do you think the total car traffic in the Boston area today is greater than it would have been had the Big Dig not been built? If yes, the ‘infrastructure naysayers’ were correct.
Of course, this means new highways can be locally beneficial, for example when they are used to divert car traffic from a city center. But they still deepen the overall car dependency. Investing in rail-bound transportation while imposing heavy fees on car traffic into the city would likely be a better use of resources.
It’s probably gone down, actually, at least in per capita terms. Boston’s population is a lot bigger than it used to be, so that has to be taken into account.
The comparison is between today and ‘today but without the highway’, not between today and before the highway was built. If the population increase is greater with the highway there, that’s still part of the induced demand.
Boston is far from car dependent; it’s probably one of the worst cities in America for drivers, and best for cyclists and pedestrians.
A city being “bad for drivers” is not a great indicator of it not being car dependant. Cities in the Netherlands are probably the most walkable and bikable on the planet, and also great to drive in because there are hardly any cars.
"Progress" (lemmy.world)