21785_om_not-searchable
/en/transport-og-reiseliv/statistikker/lbunasj/arkiv
21785_om
statistikk
2008-10-22T10:00:00.000Z
Transport and tourism
en
false

Road goods transport by Norwegian lorriesQ1 2008

Content

About the statistics

Definitions

Name and topic

Name: Road goods transport by Norwegian lorries
Topic: Transport and tourism

Responsible division

Division for Energy, Environmental and Transport Statistics

Definitions of the main concepts and variables

Carrying capacity

Carrying capacity is the differnce between the maximum permissible weight of the vehicle and the sum of the unladen weight of the vehicle and the weight of driver (75 kg).


Total weight of the vehicle -- The maximum permissible weight of the vehicle included people and goods.


National road goods transport -- Transport of goods with both loading and unloading in Norway.


International road gods transport -- Transport between Norway and another country, loaded or unloded.

Includes cross-trade (transport between two other countries) and cabotage (transport within another country)

Transport for own account -- Transport of own goods on own account.


Transport for hire or reward -- The carriage for remuneration of persons or goods on behalf of third parties


Vehicle-kilometres -- Driven kilometres with and without load.


Tonnage carried -- Gross weight of the transported goods, packaging included.

Does not include the weight of container or swap body.

Goods transport performance -- The transport work which is performed when a vehicle carries a certain amount of goods over a definite distance.

The weight of the goods in one transport operation multiplied by the transport distance of the operation. Is measured by the unit tonne kilometre.

Rate of empty kilometres -- The percentage share of unloaded vehicle-kilometres.


Commodity -- Type of commodity defined according to the EU's standard goods classification for transport statistics. Up to the 4th quarter of 2007 the NST/R nomenclature was used. The NST 2007 nomenclature was introduced as from the 1st quarter of 2008. The nomenclatures are described in the Database for standard classifications

Volume goods -- The weight of the cargo is less than the vehicle's carrying capacity when the cargo-hold's volume is fully utilised.

Standard classifications

NST 2007: Commodity codes (as from 1st quarter of 2008) NST/R: Commodity codes (up to 4th quarter of 2007) ISO 3166: Country codes NUTS 3: Region codes for the EU and Norway.

Administrative information

Regional level

For national transports the lowest level of reporting transports is municipality (to or from). The lowest level of publishing is county (NUTS 3 region). For international transports the lowest level of reporting transports is NUTS 3 region for the EU and Norway, and country for other countries. The lowest level of publishing is country.

Frequency and timeliness

Frequency: Quarterly. Timeliness: Transmission of data (to Eurostat) for each quarterly period of observation shall take place within five months of the end of the relevant quarter.

International reporting

Transmission of data to Eurostat for each quarterly period of observation.

Microdata

Data are saved at micro level.

Background

Background and purpose

The purpose of the survey is to describe the transport performances of Norwegian goods vehicles in order to get a good view of the main developing trends in the road goods transport in Norway.

The first lorry survey was conducted in 1954, the second one in 1963, and then subsequently every five years until 1993. The survey has been conducted quarterly since 1993. The international lorry survey was first conducted in 1996.

From the first quarter of 2003 the lorry survey includes both national and international transports, and all transports are reported on the same questionnaire.

Users and applications

The statistics are primarily used by public authorities and research institutes (Institute of Transport Economics, SINTEF, Directorate of Public Roads etc.) in transport planning and transport models. Transport companies and transport planners are also major users. In Statistics Norway the material is included in calculations of domestic transport performances and provides a good foundation for analyses of competitive interfaces. Figures from the surveys are also included in the national accounts and in the energy account.

Equal treatment of users

Not relevant

Coherence with other statistics

Data from the survey are used in the national accounts, resource account and energy account, and in the domestic transport performances statistical system.

Legal authority

Statistics Act § 2-2, 2-3.

EEA reference

Council Regulation (EC) no. 1172/98. Commisison Regulation (EC) nr. 2691/1999, nr. 2163/2001, nr. 6/2003, 642/2004, 1304/2007, 833/2007

Production

Population

The population is all Norwegian goods vehicles with a carrying capacity of 3.5 tonnes or more and up to a total weight of 35 tonnes. The survey does not include vehicles older than 30 years.

Data sources and sampling

The main source of information in the lorry survey is quarterly representative sample surveys based on questionnaires. Additional technical information on the vehicles is also obtained from the Directorate of Public Roads' Register of Vehicles, which is coupled with the information from the questionnaires.

From the population of about 40 000 goods vehicles a sample of approximately 1800 vehicles is drawn every quarter. The population is stratified before the sample is drawn (see 3.6).

Collection of data, editing and estimations

Approximately 140 questionnaires are sent out each week throughout the year. The deadline is three weeks after the end of the reporting week. It is also possible to report via an Internet application. The Directorate of Public Roads' Register of Vehicles is used to find the carrying capacity for the trailers used in the transport.

Mathematical and logical controls are integrated in the data input process to check for recording errors or other obvious errors in the data. The respondent is contacted in the event of partial non-response or other significant errors. Some types of missing answers are estimated using valid data for the same variable.

The population is divided into one national (NS) and one international (IS) superstratum. IS includes vehicles belonging to transport companies with a permit for international haulage - and that, according to a mapping in these companies, are likely to drive abroad, while the rest of the vehicles form NS. Subsequently these two strata are each divided into region, vehicle group and age of vehicle. Norway is divided into four regions by aggregating counties. There are six vehicle groups categorized by type of vehicle and carrying capacity. There are three age groups for NS and two age groups for IS.

The grossing up is carried through in five steps. In step 1 the weights are made that are grossing up the results from the usable questionnaires (see 5.2) to the sample. A non-response model is used to correct the skewness due to non-response. The stratification is taken into consideration. In step 2 the weights from step 1 are combined with the sample weights from the sample drawing, and the sample is grossed up to national level. In step 3 the combined weights from step 2 are calibrated against the updated population from the survey quarter. This way we get the correct amount of vehicles in NS and IS, devided into region, vehicle class and type of transport (hire or reward/own account). The information given from the vehicle owner is for one specific week in the survey quarter. To estimate the transport performances in the quarter the calibrated weight is multiplied by a week-weight that is 13 for all weeks and all vehicles. In step 4 an adjustment of this weight is made to correct for under-reporting. The basis for this adjustment is a comparison between the average length of journey from the survey and the length of journey according to mileage information from the MOT data. The adjustment is made by one factor for each of the six groups for the age of the vehicle (two groups) and type of transport (two groups). In addition, the international transport is calibrated against figures on total imported and exported quantity of goods from the statistics on external trade. This last step was introduced as from 1st quarter of 2006.

Seasonal adjustment

Not relevant

Confidentiality

Not relevant.

Comparability over time and space

In spite of minor changes in the way the lorry survey has been carried through, it is possible to follow the main trends in the development in transport performances back to 1963. Historical statistics give some main results from the previous surveys. Quarterly statistics go back to 1993.

Results from the lorry survey published before the first quarter of 2000 are not directly comparable with the tables published between the first quarter of 2000 and the fourth quarter of 2002. The reason for this is that goods vehicles with a carrying capacity between 1 and 3.5 tonnes are no longer in the population from the first quarter of 2000. Apart from the fact that the small lorries are no longer included in the survey, the results are comparable on a vehicle-level.

From the first quarter of 2003 the survey method has been changed, as well as a new questionnaire taken into use. Therefore the results from 2003 will not be directly comparable with the results from the surveys carried through before 2003. Nevertheless it is assumed that the main trends in the development in the lorries’ transport performances can be followed.

As from the first quarter of 2006, the method of grossing up the international transports has been changed in that the results are calibrated against figures on imported and exported quantity of goods from the external trade statistics. The statistics on international transports referring to periods before 2006 are therefore not comparable with the statistics on international transports from 2006 on.

The sample was reduced from 2400 to 1800 lorries per quarter from first quarter 2007. The reduction is made in the international stratum which has been halved from 1200 to 600 cars. This is done after the introduction of a yearly mapping of which lorries that are expected to drive abroad. The mapping is done among firms having a licence to perform international transports.

Accuracy and reliability

Sources of error and uncertainty

The questionnaire has gone through different types of testing, and several questions have been modified to make it easier for the respondent to answer the questions correctly. The weight of the goods is sometimes reported in thousand kilos where the unit is kilos. These errors are corrected in the manual revision.

The concepts "degree of loading" and "shipment" are sometimes misunderstood. The degree of loading is in some cases reported for weight and not volume. Sometimes more than one commodity is reported for the same shipment. These errors shall be discovered and corrected in the manual revision.

The vehicle owners are asked to give information about all their transport activities during a specified week. The respondent must therefore keep a daily log. If the use of the vehicle is not recorded every day, journeys can easily be forgotten when filling in the form. In some cases more than one driver may use the vehicle and the person filling in the form does not have a full overview of the use of the vehicle during the survey period.

Errors in the data-input may occur.

It is assumed that possible measuring and processing errors have not caused systematic errors in the results.

Unit non-response is when we fail to reach vehicle owners because of unknown address etc but have not been registered as de-registedred or refusals. The unit non-response is approximately fifteen per cent. Unit non-response contributes to the skewness and an uncertainty added to the uncertainty due to sampling errors. Step 1 in the grossing up procedure (see 3.6) seeks to correct the skewness and reduce the uncertainty due to non-response.

Item non-response is when information is received for some questions but not all, and it is possible to use the data provided. In some cases the weight of the goods has not been reported, and in these cases the weight is estimated using information on the same commodity in the rest of the data.

Sampling errors are errors that may arise in areas subject to sampling. On average, the sampling error for all samples is zero. For the lorry survey the sampling errors occur on two levels: when the sample is drawn and when the specific survey week is assigned to the vehicle. Stratification before the sample is drawn (see 3.6) has the intention of reducing the sampling error.

There will be errors in the register used to draw the sample due to time gaps in registration. For vehicles that are sold, deregistered or scrapped just before or during the relevant quarter, the information will not be accurate. The calibration carried through in step 3 in the grossing up, is done to correct these errors. Lack of information about which lorries that are used for transports abroad and also under-reporting of these transports, may up to 4th quarter of 2005 have led to too low figures on international transports. The calibration of the total quantity of imported and exported goods against the external trade statistics, introduced as from 1st quarter 2006, will correct these figures. This method may on the other hand lead to disalignment in the figures on country- or commodity level. In addition to this, there will be uncertainty in connection with the adjustments made in step 4 of the grossing up. Quantitative measures for sampling errors and other sources of error have not been estimated.

Revision

Not relevant