Auris Hybrid fuel economy and emissions figures published

It's getting close to launch day for the Auris Hybrid (this Thursday, 1 July 2010) so I've been looking at the UK government website for fuel economy and emissions - these have to be printed on the official registration document so they'd have to be prepared and submitted before the first car could be sold.

The results are:

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8
0	Model	Urban	Extra-Urban	Combined	CO2	CO	HC	NOx
1	Auris T4 with 15" wheels	3.8	3.8	3.8	89	171	34	6
2	Auris T4 with 17" wheels	4.0	4.0	4.0	93	171	34	6
3	Auris T Spirit	4.0	4.0	4.0	93	171	34	6
4	Prius T3	3.9	3.7	3.9	89	258	58	6
5	Prius T4	4.0	3.8	4.0	92	258	58	6

Urban, Extra-Urban, Combined fuel economy in L/100km. In miles per imperial gallon:

	Column 1	Column 2
0	L/100km	mpg(I)
1	3.7	76.4
2	3.8	74.3
3	3.9	72.4
4	4.0	70.6

CO2 emissions in grams per kilometre. CO, HC and NOx in milligrams per kilometre.

I'm surprised that CO, HC and NOx are identical with the different sizes of tyre, while economy and CO2 emissions change. It smells of a transcription error or not doing the test repeatedly.

I'm not really surprised to see that in the urban part the Auris comes out better than the equivalent Prius (15" wheels), as the Auris is a bit lighter and this part of the test has a lot of acceleration and almost no constant-speed driving. In the extra-urban part the Auris is weaker because it experiences more drag (higher drag coefficient).

With the prices at only £500 cheaper for an Auris T4 compared to a Prius T3 - which have roughly equivalent equipment - it's a real toss-up. If you do predominantly city driving the Auris may be slightly better; if you do a lot of high-speed cruising the Prius should be better.