You can do lots of things with an internet. Like get car sales figures going back to the 50s. And all the car lengths. Widths. Weights... And then you can stick them on a spreadsheet and work out an average size of a best selling car. And then you can make an animation.
So since the 1960s, your typical best selling motor (averaged from decade Top 10 sales) has grown by 16% in width, 7% in length and 23% in overall footprint.
In the same period, the weight has gone up 51% (from 0.84t to 1.27t) and the engine power by 93% (!) from 51hp to 98hp to lug all that excess weight around ever quicker
If you standardise all the results to 1960s = 1, you can see how cars have changed in size, weight and power since then. Bearing in mind these are the best sellers, so representative of the lower end of the market 
Observations would be car size/weight dropped 1950s-1960s, probably because the main models sold shifted from larger cars bought by the more wealthy, to smaller and cheaper ones for the aspiring middle classes
Engine size dropped back from 1970s - 1980s, probable reasons = fuel crisis of 1970s and the appearance of large numbers of small cars as 2nd vehicles, your Novas, Fiestas, Metros etc.
It's interesting that, at this end of the market, how little the car length has changed, possibly it's because the space required for 4/5 people and their luggage hasn't changed that much, and they have grown wider instead to accommodate required extra comfort space
At the other end of the market, things are just plain silly. Also, bear in mind you can get "hybrid" versions of some of these "cars" that are in the bottom VED tax bracket
I also note that the car industry has the cheek to call this list of best-sellers "sub compact SUVs".
As a reference point, your classic Mini is 1.39m wide, 3.05m long, had an entry weight of 0.58 tonnes and had 33 horses under the bonnet
Anyway this got me thinking all about speed limits, because those essentially haven't changed as a standard in urban environments since they were set at 1934. You need to enact an order to change them to 20mph.
So if you think about the kinetic energy your typical 1930s car, at 0.62t had at 30mph, the same kind of car in 2018 now weighs 1.27t. So it's twice as heavy, it has twice the kinetic energy at same speed
Long story short, because E(K) = m V squared, your 1.27t 2018 car needs to go at 21mph to have the same energy as your 1930s car
Anyway, the morale of the story is that cars are much bigger, heavier and more powerful than ever, even at the popular end of the market. And that it is well past bed time.
