A reported asked what happened in transportation this year. While the field of transportation is slow moving, a few things came to mind:
The Stockholm congestion tax trials were held this year a referendum
will be coming up soon . This is an important experiment both in the technology, but also in public acceptability of using tolls to help regulate traffic (other examples are in London and Singapore), but in Sweden there will actually be a referendum on the subject.
In general tolling is coming back as a means to pay for roads and to manage traffic, see
Ken Orski's article.
Privatization is also a related and important trend, as Indiana sold off a concession for their toll roads to Australian-based Macquarie Infrastructure Group
Hybrid vehicles broke X% market share in US (from 0% 5 years ago), but what is X is a bit hard to track down. see this article for an example
US road deaths rose for first time in 20 years according to this article
On the other hand, there have been no large commercial airplane crashes in US in several years (since 2001) (which I believe is the longest timespan between large crashes since the onset of large planes) according to this wikipedia entry
The ULTra PRT system started construction at Heathrow, will be first operational personal rapid transit system when it opens in 2008
Energy prices reached their highest (inflation unadjusted levels) in 2006.
The Big Dig of course faced some difficulties this year with the failing construction.
More historically, 2006 was the 50th anniversary of the US Interstate Highway System