A cumulative 3,000,000 miles is nothing. The US Bureau of Transportation Statistics estimates there are over 3,000,000,000,000 miles of vehicle traffic per year.[1] The estimated number of fatalities is around 50,000. There is no way to assess whether there will be fewer or more traffic fatalities with current AV technology given the limited amount of data.
As for the unlikely terrorist bit, just in case you weren't around when 911 happened: even mathematically inclined people were shocked. Not only was it the most lethal attack on American soil (nearly 3,000 dead), it was a foreign attack. People genuinely didn't know what was going to happen and were living in fear for a while. Unfortunately, some people still carry those fears to this day. Even though the numbers don't back them up, I wouldn't be so quick to
dismiss their emotions and I certainly wouldn't attack them for the all too human mistake of misattributing risk.
As for the unlikely terrorist bit, just in case you weren't around when 911 happened: even mathematically inclined people were shocked. Not only was it the most lethal attack on American soil (nearly 3,000 dead), it was a foreign attack. People genuinely didn't know what was going to happen and were living in fear for a while. Unfortunately, some people still carry those fears to this day. Even though the numbers don't back them up, I wouldn't be so quick to dismiss their emotions and I certainly wouldn't attack them for the all too human mistake of misattributing risk.
[1] https://www.bts.gov/content/us-vehicle-miles