After more than a decade of painful NOx and particulate emissions regulations, things got interesting in altogether new ways with a 2010 decree by President Obama that the EPA, working with the National Highway Traffic Administration, should attack things differently.

The 2014 fuel economy and greenhouse gas regulations, finalized in August 2011, are known as Phase 1 of a longer-term GHG plan. Given the breadth of applications in the truck world, they're complex and at first blush seem arbitrary. The GHG targets are mainly carbon dioxide (CO2) but also methane and nitrous oxide.

Official projections tell us that this effort will save 530 million barrels of oil, 270 million metric tons of GHGs, and US$50 billion in fuel costs.

The rules divide trucks into three groups, starting at 8,500 lb GVW, thus including medium- and heavy-duty pick-ups and vans, trailer-pulling tractors, and vocational vehicles. Note that whole tractor-trailers are not targeted.

Starting with 2014, tractors must achieve as much as a 20% reduction in CO2 emissions and fuel consumption by 2017. There are separate engine standards; heavy-duty engines had to have a 3% improvement last year rising to 6% by 2017.

For heavy-duty pickup trucks and vans, the standard demands a phased-in improvement reaching 15% by the 2018 model year.

Mixers, refuse haulers, and other vocational machines have to get to a 10% reduction in fuel consumption by 2017. Again, separate engine standards apply, which called for a 5% improvement last year, rising to 9% by 2017.

In practice, none of this caused a stir last year, and by all accounts targets were met with ordinary improvements of existing hardware and software. Obviously, things will get tougher as 2017 approaches but it's unlikely that radically new hardware -- like waste-heat recovery -- will be required.

And Phase 2?

A great deal of controversy already surrounds this next phase of the fuel economy and GHG reduction effort, as President Obama demanded in February of last year. Nothing is yet clear.

We do know that the second phase will demand even tougher carbon dioxide and fuel-consumption reductions in heavy- and medium-duty trucks. And we know that we'll see the first draft of a rule in June followed by a final regulation some time in 2016. (Originally the draft was due in March.) Our firm knowledge stops there.

It's likely that testing procedures will change. Phase 1 is being dealt with entirely by computer modelling, and while that general approach is likely to continue, things seem bound to get more rigorous.

Among the key issues is whether trailers should be added to the mix. It's likely, and it's equally likely that certain aerodynamic devices will be required.

The biggest single issue may be the way engines are dealt with. There are two camps, one saying they should continue to be tested separately, the other -- not surprisingly led by the truck makers with their own diesels -- urging that the whole truck should be tested.

We'll have a closer look at this and other Phase 2 issues in the next installment.