Report - DCE - Nationalt Center for Miljø og Energi

The number of urban buses has been almost constant between 1985 and
2010. The sudden change in the level of coach numbers from 1994 to 1995 is
due to uncertain fleet data.
The reason for the significant growth in the number of mopeds from 1994 to
2002 is the introduction of the so-called Moped 45 vehicle type. For motorcycles,
the number of vehicles has grown in general throughout the entire
1985-2010 period. The increase is, however, most visible from the mid-1990s
and onwards.
The vehicle numbers are summed up in layers for each year (Figure 3.84) by
using the correspondence between layers and first year of registration:
1
,
=
(
)
∑
1
,
=
(
)
Where N = number of vehicles, j = layer, y = year, i = first year of registration.
Weighted annual mileages pr layer are calculated as the sum of all mileage
driven pr first registration year divided by the total number of vehicles in
the specific layer.
0
(
)
∑
1
,
=
( )
,
(
= )
1
∑
⋅ 0
,
=
(
)
,
Since 2006 economical incitements have been give to private vehicle owners
to buy Euro 5 diesel passenger cars and vans in order to bring down the particulate
emissions from diesel vehicles. The estimated sales between 2006
and 2010 have been examined by the Danish EPA and are included in the
fleet data behind the Danish inventory (Winther, 2011).
For heavy duty trucks, there is a slight deviation from the strict correspondence
between EU emission layers and first registration year.
In this case, specific Euro class information for most of the vehicles from
2001 onwards is incorporated into the fleet and mileage data model developed
by Jensen et al. (2011). For inventory years before 2001, and for vehicles
with no Euro information the normal correspondence between layers and
first year of registration is used.
Vehicle numbers and weighted annual mileages pr layer are shown in Annex
2.B.1 and 3.B.2 for 1985-2010. The trends in vehicle numbers pr layer are
also shown in Figure 3.84. The latter figure shows how vehicles complying
with the gradually stricter EU emission levels (EURO I, II, III, IV etc.) have
been introduced into the Danish motor fleet.