18 trains a day? We have lots of lines here with much less than that with some very strong safety features. I don't call that arrogance, I call it sensible.
You can't run a passenger carrying train in the UK without them and frankly I'm amazed that you actively defend it.
If that's arrogant then whatever.
Okay, quiet day, so I want to expand on Ameecher's response here, with an example of one of the least used (but still somewhat regularly used) lines in the UK: Fort William - Mallaig. The Fort William - Mallaig line sees 4 trains, per direction, per day (8 total) under the current timetable. This increases to 6 trains, per direction, per day (12 total) in the Summer Months when the Jacobite (twice-daily steam services run by West Coast Railways) is running. It is located in the rural Scottish Highlands, and links a town of 10k people, with a port town, which has a population of just 800. The journey generally takes about 83 minutes from end to end.
The line is single track from Fort William Jn to Glenfinnan (15 miles out of Fort William), where there is a passing loop, it's then single track until Arisaig (32 miles from Fort William, 7.5 miles from Mallaig), where there is another passing loop, and the line is then completely single to Mallaig. The signalling on the line is provided via the Radio Electronic Token Block (RETB) system. This is basically a development of the physical token system (which itself still sees limited usage in the UK).
Effectively, under RETB, a driver of a train will radio the signaller, tell them where they are (and where they want to go where applicable), and if the section ahead is clear, the signaller will issue the respective token for the next section, which is shown to the driver on an electronic display in the cab. A second token can then not be issued, which ensures a signaller cannot accidentally clear two trains onto the same section.
However, what happens in the event of a train not cleared for the section trying to enter it? Well, the majority, if not all the block sections are now also protected via TPWS, which will, in the event of attempting to pass onto the section without a Token, cause the brakes on the train to apply. TPWS can be manually overridden, so doesn't prevent a case of drivers intentionally passing onto a section, however, one would hope no driver would want to do such.
So yeah, these are the safety systems in place for a line that sees just 8 trains per day, so the fact that the US justifies lack of safety by the fact it sees "only" 18 trains per day is a bit silly in my personal opinion. After all, these trains on the Mallaig line are an inconsequential factor of the roughly 22,500 trains run each day in the UK.If you want to read more about RETB: click here
Source for number of daily trains in the UK (does not include Metros/LU): click here
Mallaig Timetable: click here (Note: those labelled SHIP are actually ships, and therefore not included in this).