> And, in such circumstances, your best bet is to drive west.
Hmm. Given that public transit stations are deep below the earth, and many huge buildings have deep underground space: would it be more effective to wait 8h underground and then try to escape over the fallout-laden city than to be aboveground, stuck in traffic and perish with the fireball?
The radiation risk from fallout is goverened by the seven-ten rule: Each order of magnitude of seven increase in time (counting from one hour after detonation) reduces fallout by a factor of ten.
After 7 hours: 10%, after 49 hours (~2 days): 1%, after two weeks, 0.1%.
This is highly influenced by blast yield, type, elevation, and prevailing wind direction.
The other problem with being in tunnels is the shock wave itself. That can collapse the tunnel, of course, but also kill directly through blast trauma. Blast is attenuated as the cube of distance, so an increased range from the blast itself will tremendously reduce those effects (and similarly the prompt radiation and thermal effects).
You would likely be better off waiting longer than 8 hours to be rescued; inhaling a bunch of radioactive dust is likely going to be a much worse death than being vaporized by heat, or smashed to death by the blast wave.
Hmm. Given that public transit stations are deep below the earth, and many huge buildings have deep underground space: would it be more effective to wait 8h underground and then try to escape over the fallout-laden city than to be aboveground, stuck in traffic and perish with the fireball?