America has a huge amount of factors which are different to the UK.
Typically higher summer temperatures and colder winter temperatures in most places than the UK. We have a very mild climate, which means that in the event a child is forgotten/left in a car, even for hours, most of the time they will be fine if a bit bored/hungry.
Very poor provision for parental leave meaning parents often have to return to work when their babies are very little meaning they are dealing with newborn stuff plus work stress on very little sleep.
Poor employee rights in general meaning many parents work long hours (over 40 per week) and only two weeks' holiday a year total, very little sick leave and expectation that you'll work even if not your best. Total expectation that your focus should be on the job, not other things.
Different infrastructure around workplaces and car parking meaning it is quite unlikely for somebody to walk past an unattended car, and cars may well be far enough from windows/walkways for anybody to hear a baby crying, yet still in open car parks, rather than underground or multi-storey which would afford some protection from sun. Work districts are usually fairly far from homes meaning that parents may have a long (compared with UK) commute which adds to the tiredness.
For some reason - I don't know why, as this is not law in the UK - UK childcare settings tend to have a policy of calling if a child is not dropped off according to their usual schedule, whereas this policy is not common in the US.
Possibly a difference in car seat practices. In the UK most parents use a portable baby seat which they only have in the car when a baby is in it until this seat is outgrown at which point they change to a forward facing seat. So there is always a visual reminder that the child is in the car. In the US, the portable baby seats are typically smaller, but there is an official recommendation to rear face until 2 years old which means that it's common to switch to a "convertible" seat at about 6-9 months, or sometimes to use one of these from birth - where the seat is always present in the car but it is not immediately obvious whether there is a child in it. Of course there are ERF seats in the UK too and some people use a permanently fixed car seat from birth but it's much more common in the US.
Plus there is a higher population, of course, so they will have higher numbers of anything. 37 children in a year is 37 too many, but it's also a miniscule number in relation to all population of the US.