Most steam cars use the exhaust pulse coming from the cylinders, to pull fresh air into the burners. Large steam trains do the same thing, so exhaust piping is critical for good combustion. It will be interesting to see the final car. Safety is always something to think about, but the steam cars were no more dangerous then anything else on the road. Stanley had a ton of piano wire wrapped around the boilers so if it ever did explode, it would blow the top or bottom off, away from the driver. My uncle studied the Stanley's for years and never found a credible report of a boiler explosion. They buried one in the ground and set off to explode it as a test, it was well over 600 psi before giving out! They don't make as much steam as you would think, see videos above.