A lot of people seem to consider greenhouse emissions consideration numero uno in guiding the direction in which automakers need to go in the future. As a happy coincidence, lower carbon dioxide emissions also equate to greater fuel economy.
And yet, the alternatives available to consumers to lower emissions and increase economy are either unpalatable to the common consumer or too expensive.
A car like the Suzuki Alto will get you up to and over the 30 km/l mark, but concerns over safety and useable space turn off buyers looking for something more like their Toyota Corolla.
A Toyota Prius will also do over 30 km/l, but it's twice as expensive as said Corolla, as well.
In Europe, buyers have long had the diesel option, yet locally, diesel cars are the exception, rather than the norm. While modern common rail diesel SUVs and compact SUVs are quite popular, diesel cars are less so. The trouble is that modern diesel cars cost more than their gasoline counterparts. Only Hyundai and Ford are bothering to attack this market. While Ford has the benefit of a local factory, which gets them tax breaks, Hyundai has to make do with CBU (completely built up) units from Korea.
Which is why the Elantra never really got off the ground. Will the i30 be any different? One would hope so. The i30 doesn't break any new ground as a motor vehicle per se, but the economy of that 1.6 liter diesel cannot be denied.
EDIT: As an aside: Why do people always seem to think that journalist review economy is any different from user economy? It's not like we go out of our way to game a car's economy to make it look great. Far from it, in fact. Most "motoring journalists" drive like maniacs.
Just because I get higher numbers than you doesn't mean I don't know anything about measuring economy (in fact, quite the opposite)... it just means my route is less congested than yours and that I drive gentler.
No two people will ever get the same economy. I don't get the same economy on different days. On the Focus TDCi, for example, I got as low as 7 km/l on one 3 kilometer school run (though this was done long after the review), averages of 11-13 km/l in traffic on our regular 20 kilometer commute, 9-11 km/l in heavy traffic on a 15 kilometer trip, and 20 km/l on the highway.
Some people see the highway numbers, do a run in rush hour traffic, taking an hour to go just two or three kilomters, and think we're pulling these numbers out of our butts. We're not. Your driving route sucks. Buy a bicycle and get over it.
Seriously... unless you're driving for little kids or old ladies... what's wrong with walking or biking?