But interstates only make sense because of local roads. If local roads didn't connect to the interstates, then we can discount them from the equation.
Personally, I think people should be paying more for using the roads. From what I can tell, most states' use related taxes (gas taxes, registration taxes, etc) account for less than half of total road funding. This makes driving artificially cheap compared to mass transit options, to the point where it's often cheaper to drive than to take a bus or train, which is absolutely ridiculous. For example, my commute is ~10 miles, and the IRS claims this costs me $5 (~$0.50/mile). I did some math and estimate that my costs are closer to $0.30/mile, probably less (insurance, registration, gas, maintenance). A bus ticket is $2.50 each way. The bus takes >40 minutes assuming I ride my bike there, >60 minutes if I walk, and driving takes ~20 minutes.
Assuming my state funds roads ~50% with income taxes, switching this over to purely use-based taxes (gas and registration taxes) would likely double my driving costs, making mass transit make sense financially, as it should. It certainly uses less resources to take the bus than drive, so it should also be cheaper. Yet it doesn't look that way according to my calculations.
Also, taking Amtrak is often more expensive than taking an airplane, even if direct routes exist, and it takes way longer. Amtrak should be way cheaper than flying, yet at best it's a wash, but usually way more expensive. We need faster, cheaper trains, and trips within 800 miles should be competitive with airlines (<6 hours, about the same price or cheaper than flights).
> It certainly uses less resources to take the bus than drive
In terms of road maintenance, that might actually not be the case. Road destruction by traffic scales with the fourth power of axle load, for weak pavement surfaces and heavy loads with the sixth (!) power of axle load.
(Of course you are right with respect to traffic congestion, CO2 emissions, particulate pollution and noise pollution.)
Most states have too many roads and not enough money to even pay for the ones they have. Another second over negative effect of roads is that people will build wherever there are decent roads to get there. In order to preserve natural areas, the best way to do so is to just make sure there are no good ways to get there.
Personally, I think people should be paying more for using the roads. From what I can tell, most states' use related taxes (gas taxes, registration taxes, etc) account for less than half of total road funding. This makes driving artificially cheap compared to mass transit options, to the point where it's often cheaper to drive than to take a bus or train, which is absolutely ridiculous. For example, my commute is ~10 miles, and the IRS claims this costs me $5 (~$0.50/mile). I did some math and estimate that my costs are closer to $0.30/mile, probably less (insurance, registration, gas, maintenance). A bus ticket is $2.50 each way. The bus takes >40 minutes assuming I ride my bike there, >60 minutes if I walk, and driving takes ~20 minutes.
Assuming my state funds roads ~50% with income taxes, switching this over to purely use-based taxes (gas and registration taxes) would likely double my driving costs, making mass transit make sense financially, as it should. It certainly uses less resources to take the bus than drive, so it should also be cheaper. Yet it doesn't look that way according to my calculations.
Also, taking Amtrak is often more expensive than taking an airplane, even if direct routes exist, and it takes way longer. Amtrak should be way cheaper than flying, yet at best it's a wash, but usually way more expensive. We need faster, cheaper trains, and trips within 800 miles should be competitive with airlines (<6 hours, about the same price or cheaper than flights).