As with every major political change in the EU, this one has been discussed for years, and there are even annual global conferences focused on the issue. EU and third-party studies have shown that vehicles are emitting particulates from diesel engines, CO2, and nitrogen oxide at sometimes much greater rates in real-world driving than they do in their certification tests. One investigation by the International Council on Clean Transportation found NOx emissions seven times higher on average, and only one car out of 16 in compliance with a proposed EU standard of 80 grams per kilometer. The EU itself has found that automakers game the NEDC test through methods like software programming, making their cars get into a low-emissions mode when their front wheels are on a dyno and the rear wheels aren't moving. The new on-road tests are said to use a portable emission measurement system, but no one knows yet what that test will look like.
The European Automobile Manufacturers Association (ACEA) and the UK's Society of Motor Manufacturers and Traders (SMMT) are contesting the timing, technology, and test protocols of the EU initiative, even though they are publicly in favor of reducing emissions. But the ACEA sent the EU its own draft proposal with new timelines and testing methodologies that went too far, and was thrown out. The EU wants to have a final decision on the new testing this year, with implementation set for 2017, but the ACEA and SMMT decry the expense of re-engineering cars that are in right now in the middle of development cycles, and trying to do that to pass tests that haven't been created yet. As far as that goes, they have a point, but they appear resigned to the fact that the 2017 change will arrive as planned.