Lets see if we can't reduce some of the speculation about sonic booms damage. The info below is from the Wiki article, my comments/questions are in red.
A vehicle flying at greater altitude will generate lower pressures on the ground, because the shock wave reduces in intensity as it spreads out away from the vehicle, but the sonic booms are less affected by vehicle speed. US SSTs were projected to fly at 70,000', but even if this wasn't reached 50-60,000' is still pretty high.
Aircraft Speed Altitude Pressure (lbf/ft2) Pressure (Pa)
SR-71 Blackbird Mach 3+ 80,000 feet (24,000 m) 0.9 43
Concorde (SST) Mach 2 52,000 feet (16,000 m) 1.94 93
F-104 Starfighter Mach 1.93 48,000 feet (15,000 m) 0.8 38
Space Shuttle Mach 1.5 60,000 feet (18,000 m) 1.25 60
Buildings in good condition should suffer no damage by pressures of 530 Pa (11 psf) or less. And, typically, community exposure to sonic boom is below 100 Pa (2 psf). Ground motion resulting from sonic boom is rare and is well below structural damage thresholds accepted by the U.S. Bureau of Mines and other agencies. The US SST sonic boom was expected to be some 1/3 worse than the Concorde, so maybe 3 lbf/ft2 or about 1/4 of the level that will cause no damage to well maintained buildings.
Ground width of the boom exposure area is approximately 1 statute mile (1.6 km) for each 1,000 feet (300 m) of altitude (the width is about five times the altitude); that is, an aircraft flying supersonic at 30,000 feet (9,100 m) will create a lateral boom spread of about 30 miles (48 km). SST would create a sonic boom carpet ~50-60 miles wide, the US is over 2000 miles wide from north to south so 3 or 4 east-west flight paths will cover a miniscule amount of land in CONUS.
For a boom to reach the ground, the aircraft speed relative to the ground must be greater than the speed of sound at the ground. For example, the speed of sound at 30,000 feet (9,100 m) is about 670 miles per hour (1,080 km/h), but an aircraft must travel at least 750 miles per hour (1,210 km/h) (Mach 1.12, where Mach 1 equals the speed of sound) for a boom to be heard on the ground. So an SST can travel at transonic speed without the sonic boom reaching the ground, so could fly transonic over the eastern half of CONUS.
As an aside, horses get spooked by EVERYTHING and get used to things if exposed to them. If we were going to limit human activity to what doesn't initially spook horses then we wouldn't have trains or cars, horses and other animals would get used to semi-regular sonic booms.
Bear in mind that the political issues raised by mitigated sonic booms have to be weighed against the employment generated by SST production and the other powerful interests that would use SSTs from the power centres on the US coasts. If the SST programme progresses better then I think the political environment will change to make it work.
A vehicle flying at greater altitude will generate lower pressures on the ground, because the shock wave reduces in intensity as it spreads out away from the vehicle, but the sonic booms are less affected by vehicle speed. US SSTs were projected to fly at 70,000', but even if this wasn't reached 50-60,000' is still pretty high.
Aircraft Speed Altitude Pressure (lbf/ft2) Pressure (Pa)
SR-71 Blackbird Mach 3+ 80,000 feet (24,000 m) 0.9 43
Concorde (SST) Mach 2 52,000 feet (16,000 m) 1.94 93
F-104 Starfighter Mach 1.93 48,000 feet (15,000 m) 0.8 38
Space Shuttle Mach 1.5 60,000 feet (18,000 m) 1.25 60
Buildings in good condition should suffer no damage by pressures of 530 Pa (11 psf) or less. And, typically, community exposure to sonic boom is below 100 Pa (2 psf). Ground motion resulting from sonic boom is rare and is well below structural damage thresholds accepted by the U.S. Bureau of Mines and other agencies. The US SST sonic boom was expected to be some 1/3 worse than the Concorde, so maybe 3 lbf/ft2 or about 1/4 of the level that will cause no damage to well maintained buildings.
Ground width of the boom exposure area is approximately 1 statute mile (1.6 km) for each 1,000 feet (300 m) of altitude (the width is about five times the altitude); that is, an aircraft flying supersonic at 30,000 feet (9,100 m) will create a lateral boom spread of about 30 miles (48 km). SST would create a sonic boom carpet ~50-60 miles wide, the US is over 2000 miles wide from north to south so 3 or 4 east-west flight paths will cover a miniscule amount of land in CONUS.
For a boom to reach the ground, the aircraft speed relative to the ground must be greater than the speed of sound at the ground. For example, the speed of sound at 30,000 feet (9,100 m) is about 670 miles per hour (1,080 km/h), but an aircraft must travel at least 750 miles per hour (1,210 km/h) (Mach 1.12, where Mach 1 equals the speed of sound) for a boom to be heard on the ground. So an SST can travel at transonic speed without the sonic boom reaching the ground, so could fly transonic over the eastern half of CONUS.
As an aside, horses get spooked by EVERYTHING and get used to things if exposed to them. If we were going to limit human activity to what doesn't initially spook horses then we wouldn't have trains or cars, horses and other animals would get used to semi-regular sonic booms.
Bear in mind that the political issues raised by mitigated sonic booms have to be weighed against the employment generated by SST production and the other powerful interests that would use SSTs from the power centres on the US coasts. If the SST programme progresses better then I think the political environment will change to make it work.