Compact cars are popular in Australia, even though we have big open roads and most people live in the suburbs. I think running costs are a big factor in choosing a car, if you are comparing between 5L per 100KM and 15L per 100KM, and the price of petrol is around $1.40 per litre ($3.70 USD per gallon). Registration and insurance is also more expensive the bigger the engine. Once popular sedans like the Holden Commodore and Ford Falcon have all but died out, as people no longer wanted a petrol guzzling 6 or 8 cylinder engine.

I think an electric car the size of a Toyota Yaris / Honda Jazz would be a big hit in Australia, since that category has been popular for decades. Whereas I think the only popular sedan nowadays would be the Camry, and they are mainly used for taxis. Family cars tend to be SUVs with underpowered petrol or diesel engines to try and get the fuel economy, even if it struggles to climb hills.

Another big seller I think would be a plug in hybrid ute similar to a Hilux, since they are the main vehicles used by tradies. If you could get maybe 100 - 200km of travel using electric only and then petrol for the rest, I think that would be suitable for people who mainly work in metropolitan areas. You could also use the battery instead of carrying a petrol generator.