In the case of cars, according to this [1] (seemingly based on US Federal data), the improvements in car efficiency since the 60s, is:
> Noteworthy fuel-economy trends, taking into account the length of time represented:
> A minor decrease between 1966 and 1973 (from 13.5 mpg to 12.9 mpg).
> A modest increase between 1973 and 1991 (from 12.9 mpg to 19.6 mpg).
> No change between 1991 and 2004 (19.6 mpg for both years).
> A modest increase between 2004 and 2008 (from 19.6 mpg to 21.8 mpg).
> A minor increase between 2008 and 2017 (from 21.8 mpg to 22.3 mpg).
The term "modest" is probabling misleading, but looking at the graph in the linked site is more telling: basically, efficienty increased after the first gas shock, and "more or less" stalled in the 2000s.
So maybe the addition of electronics in the 70/80s had an impact in consumption, but I would argue it's less obvious for the additions in the 90s/2000s/2010s - although it would take a bit longer to show as the older cars are still on the road.
Impact on safety, though, I don't know.
As for the CO2 emission, I have a hard time taking any number at face value, knowing that, ironically, some of the electronings on board can be designed to cheat emision tests [2] - but that's probably unfair.
Electronic fuel injection definitely made cars more frugal back in the 90s. Also improved aerodynamics helped a bit. On the other hand, due to crash test requirements cars are now significantly heavier (I guess around 20%), people are also driving faster and enjoy more power and dynamics from the vehicle, which not only wastes fuel, but also leads to the use of wider tires, which are more expensive to produce and impact fuel economy negatively.
> Noteworthy fuel-economy trends, taking into account the length of time represented:
> A minor decrease between 1966 and 1973 (from 13.5 mpg to 12.9 mpg).
> A modest increase between 1973 and 1991 (from 12.9 mpg to 19.6 mpg).
> No change between 1991 and 2004 (19.6 mpg for both years).
> A modest increase between 2004 and 2008 (from 19.6 mpg to 21.8 mpg).
> A minor increase between 2008 and 2017 (from 21.8 mpg to 22.3 mpg).
The term "modest" is probabling misleading, but looking at the graph in the linked site is more telling: basically, efficienty increased after the first gas shock, and "more or less" stalled in the 2000s.
So maybe the addition of electronics in the 70/80s had an impact in consumption, but I would argue it's less obvious for the additions in the 90s/2000s/2010s - although it would take a bit longer to show as the older cars are still on the road.
Impact on safety, though, I don't know.
As for the CO2 emission, I have a hard time taking any number at face value, knowing that, ironically, some of the electronings on board can be designed to cheat emision tests [2] - but that's probably unfair.
[1] https://www.greencarcongress.com/2019/09/20190930-sivak.html
[2] https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal