Was there a single theme to this year's biennial automotive extravaganza, otherwise known as the 65th IAA International Motor Show?

Probably not, but there were plenty of underlying themes that, as they emerge, will shape the future of the car industry.

The debate over self-driving cars is hotting up while Daimler believes that the internal combustion engine will be our primary power source for at least another 20 if not 30 years.

In Germany, 40% of car industry R&D spend is on alternative powertrains, including e-mobility and e-vehicles but the view is that the internal combustion engine will not be replaced.

Just as significant though is the idea that the future of the car industry lies not in people buying cars but in cars being shared and the need to integrate private and public transport in a way not seen before. ‘Connect not cannibalise' was one phrase that lingers.

Think of the sprawling Messe, the vast 11-hall complex that is home to the show, as a town on its own and you begin to understand what this could mean. The press shuttle cars ranged in size from the BMW i3 - electric only - to the hybrid Kia Optima and the Mercedes-Benz S-Class. Silently to-ing and fro-ing between the halls picking up and dropping off journalists on demand, the shuttles, especially the i3, gave us an idea of how a megacity could operate. The Messe even has its own railway station to help complete the picture.

It's not that young people are falling out of love with cars, said one executive, they just want to engage with them in a different way.

That's something the industry is taking seriously. To those that don't, whether the internal combustion engine is still a dominant power source in 20 or 30 years will be relevant because they won't be around to worry about it.

There were quite a few who thought that the internal combustion engine is far from dead and many talked of new low emission power plants. The new Opel/Vauxhall Insignia, for example, will have an astonishing 99 g/km engine in its line up while more ICE technology is on the way from the company. Even Maserati is talking better fuel economy and emissions by introducing diesels for the first time.

So what happened to electric vehicles? They were still there of course, and BMW used its home show to show off its new ‘i' models. A fleet of i3s was ferrying journalists round the showground.

But there is concern that the market has not hit the sales numbers expected while government subsidies appear to be on the wane.

The UK figured highly because it is bucking the trend and growing strongly unlike other countries where sales continue to fall. That means everyone is looking to GB to sell their cars and with that price wars and discounts could come into play to help shift metal.

The home team players showed they are not immune from collaboration with the unveil of the co-developed Smart and Renault Clio. The political posters all round town were a reminder that an election is just around the corner and what impact will that have on the German market and auto industry?

Many journos felt there was a lack of 'buzz' around the show, perhaps because it is so large. It was difficult also to point to a stand out unveil although the Jaguar C-X17 received a big thumbs up from all who saw it.