Scottish Transport Statistics No 29: 2010 Edition

CHAPTER 11 PERSONAL AND CROSS-MODAL TRAVEL

Figure 11.1 Calls to Traveline Scotland in 2009

Note: Severe weather conditions in December 2009 caused a sharp increase in the volumes of calls.

Figure 11.2 Traveline Scotland - Web hits in 2009

1. Introduction

1.1 This chapter includes information collected from individuals via surveys like the National Travel Survey ( NTS) and the Scottish Household Survey ( SHS). Such surveys provide person-based cross-modal information, in contrast to most of the earlier chapters, which tend to be based on particular modes of transport.

1.2 The NTS is a Great Britain survey with a very small Scottish sample (see section 4.1) and so results combine years but may be subject to large percentage sampling errors (see section 3.6). Therefore NTS results should be regarded as broad indications only of the relative use of different modes of transport .

2. Main Points

National Travel Survey

Trips

2.1 The National Travel Survey's estimated average number of trips, within Great Britain, per Scottish resident per year was 978 in the two-year period 2008/09, equivalent to an average of 2.7 trips per person per day. The estimated average number of trips per person per year has remained around the range 969 to 1,100 between 1998/99 and 2008/09, with some fluctuation (which could be due to sampling variability; see section 3.6). Since 1998/99, the estimated number of trips by car has fallen by 7%, walking by 26% and bus by 13%. ( Table 11.1)

Distance travelled

2.2 Cars, vans and lorries accounted for 77% of the average 7,232 miles travelled, within Great Britain, per year per Scottish resident in 2008/09. Half this distance was as a driver, and a further 27% (1,971 miles) as a passenger. Local bus and Surface rail each accounted for 6.7% (483 miles) and 5.7% of the total distance travelled respectively. Other public transport (e.g. air, ferry, non-local bus) for 3.1% (225 miles). ( Table 11.2)

2.3 The estimated average distance travelled per person per year has decreased by 6% between 1998/99 (7,713 miles) and 2008/09 (7,232 miles), with some fluctuations during the period, possibly sampling variability. Car journeys accounted for the fall with driven journeys falling from 3,652 miles to 3,585 miles. ( Table 11.2)

2.4 The average length of a car trip has remained around 8 or 9 miles since 1998/99, local bus trips around 4 - 6 miles and train trips around 30 miles. ( Table 11.3)

2.5 In 2008/09, shopping (20%) was the most frequent purpose of a trip followed by: commuting (17%), visiting friends at home (11%), other personal business and other escort (both 10%). ( Table 11.4)

2.6 Unsurprisingly commuting journeys accounted for the largest share of the total distance travelled in 2008/09 (19%: 1,397 miles). This was followed by holiday/day trip (16% or 1,176 miles), visiting friends at home (14% or 999 miles) and shopping (14% or 986 miles). ( Table 11.5)

Duration travelled

2.7 In 2008/09, Scottish residents spent an average of 367 hours per person per year travelling within Great Britain: an average of an hour per day. This figure has not changed much since 1998/99, remaining between 339 hours and 386 hours. In 2008/09, 19% of the average hours travelled per person were for commuting. Shopping accounted for 16%. ( Table 11.7)

2.8 Since 1998/99, the average duration of travel per trip has remained between 20 minutes and 23 minutes. This is highest for holiday/day trip (down from 65 minutes in 1998/99 to 54 minutes in 2008/09) and business trips (varying between 35 and 41 minutes), and lowest for escort to education trips (around 11-13 minutes). Generally, the figures have been fairly constant since 1998/99. ( Table 11.8)

2.9 People in households with two or more cars made an average of 1,082 trips per person per year in 2008/09, about 62% less than the overall average of 2,829 trips per person per year; those in no car households averaged 754 trips per person per year, 73% fewer than the overall average. Residents of households with cars made most of their journeys by car: 66% of journeys for one car households and 77% for 2+ car households. People in households without a car averaged over twice as many trips per person by foot, and almost seven times as many trips per person by local bus, as those in households with 2+ cars. ( Table 11.9)

Scottish Household Survey

Driving

2.10 The Scottish Household Survey ( SHS) provides information about how often people aged 17 or over drive. In 2009, 50% of men, 37% of women and 43% of all people aged 17+ said that they drove every day. A further 18% stated they drove at least once a week (but not every day), 3% drove less frequently, 4% had a full driving licence but never drove, and 32% did not have a full driving licence. ( Table 11.10)

2.11 Since the survey started in 1999, the percentage who drove every day has fallen, but those who drove at least three times a week (but not every day) and once or twice a week has risen. However this may be impact by changes to the survey: previously this information was collected via the head of household or his/her spouse/partner; but since April 2003, it's collected for only one randomly-selected adult member of the household and collected directly. ( Table 11.12)

2.12 The frequency of driving varied with age. In 2009, 53% to 58% of people aged 30 to 59 said they drove every day. As age rises this falls (to 12% for people aged 80 and over). The frequency of driving also varied with the annual net income of the household. Around two thirds of people aged 17+ living in households with an annual net income of £30,000 or more said they drove every day, compared with around a fifth of those living in households with an annual net income of up to £10,000. Around a third (34%) of people aged 17+ in large urban areas drove every day compared to 60% in accessible rural areas. ( Table 11.10)

Walking

2.13 In 2009, 59% of adults made a journey of more than a quarter of a mile by foot to go somewhere in the last seven days - the highest level since the survey began in 1999. Young adults (aged 16-19) were the most likely to have walked to go somewhere (77%), compared with just over half of those in their 50s and 60s (54-56%), and just over a third of those aged 80 or above (34%). (Tables 11.11 & 11.13)

2.14 In 2009, 48% of adults said that they had walked for pleasure or to keep fit at least once in the last seven days - also the highest since the survey began. Men were slightly more likely than women to report that they had walked for pleasure or to keep fit (men: 50%; women: 47%). There was some variation with age: the percentage was highest for those aged 30-39 (57%) and lowest for those aged 80 or above (27%). There was less variation with household income, although those with net annual incomes of over £40,000 were more likely than those with lower incomes. (Tables 11.11 & 11.13)

Travel To Work ( non- SHS data)

2.16 Labour Force Survey results suggest that, between 1999 and 2009, there has been little change in the percentage for whom a car or a van is the usual means of travel to work (69% in 1998 and 70% in 2009). There was also little change to walking which fell from 13% to 12%. People who work at home are excluded from these figures. ( Table 11.14)

2.17 There appears to have been little change in recent years in the average times taken to travel to work by the main modes of transport (in 2009: 24 minutes by car; 35 minutes by bus and 14 minutes by foot). ( Table 11.15 b)

2.18 The longer-term trends are shown by statistics from the population censuses, which have collected information about travel to work since 1966. Excluding those that worked at home, the percentage of the working population using cars to travel to work has increased from 21% in 1966 to 68% in 2001 and the percentage using buses has fallen from 43% in 1966 to 12% in 2001. There has also been a significant fall in the proportion of the working population who walk to work, from 24% in 1966 to 12% in 2001. ( Table 11.16)

Travel to Work ( SHS data)

2.19 SHS data can be used in more detailed analysis of travel to work patterns. The SHS shows that 11% of employed adults worked from home in 2009, the proportion of which has been gradually increasing from 1999 (7%). Over half (57%) of self-employed people worked from home. (Tables 11.17 & 11.21)

2.20 Overall, the SHS found that the majority (67%) of employed adults who did not work at home travelled to work by car or van in 2009. This percentage varied with gender (men: 70%, women: 65%), age (16-20: 51%, 40-49: 74%), type of employment (only 60% of those who work part-time) and annual net household income (rising to 77% of those in the £40,000+ band). ( Table 11.18)

2.21 Other usual means of travel to work were: walking (12%); bus (12%); rail (4%); bicycle (2%) and other modes (2%). Use of such modes of transport also varied. For example: in general, the greater the income of the household, the less likely a person was to walk or use the bus to travel to work; the percentage who walked to work was highest in remote small towns (21%) and the percentage who commuted by bus was highest in large urban areas (19%). Since the survey started, the percentage driving to work has risen (from 54.6% in 1999 to 60.7% in 2009), the percentage of passenger and walking journeys has fallen (from 11.8% to 6.4% and from 13.7% to 12.3% respectively), and little change in the use of other modes of transport ( Tables 11.18 & 11.22)

2.22 SHS travel to work statistics underpin Scotland's National Indicator on travel to work. More information on National Indicators can be found on the Scotland Performs website: http://www.scotland.gov.uk/About/scotPerforms/indicators/publicTransport

Travel to School

2.23 In 2009, 50% of children in full-time education at school usually walked to school, 22% usually went by bus, 24% by car or van, 1% by train, 1% cycled and about 2% used other means of transport (such as taxi or ferry). There was little difference between the sexes, but varied greatly with age: 56% of primary school age pupils (those aged up to 11) usually walked to school compared with only 42% of those of secondary school age (those aged 12 and over); 31% of primary pupils went by car or van compared with only 16% of secondary pupils; and only 10% of primary pupils usually travelled by bus compared with 38% of those of secondary age. ( Table 11.19)

2.24 Those usually travelling by car/van tended to rise with household income, to (27-32%) of pupils from households with an annual net income of £30,000 or more. Walking to school was lowest (24-29%) in rural areas. The survey suggests a fall in those walking to school and a rise in those going by car since 1999. This is consistent with findings from the National Travel Survey's Scottish sample results. (Tables 11.19, 11.20 & 11.23)

Travel Abroad

2.25 According to the International Passenger Survey ( IPS), Scottish residents made an estimated 3.9 million visits abroad in 2009 with about 3.7 million visits (94%) being made by air. Glasgow was the main airport used and accounted for about 1.3 million visits (34% of all visits abroad), followed by Edinburgh (1.0 million or 27%), Prestwick (376,000 or 10%) and Aberdeen (180,000 or 5%). Around 163,000 visits abroad (4%) were made by sea, and roughly 63,000 (2%) were made using the Channel Tunnel. ( Table 11.24)

2.26 Around 67% of Scottish residents' visits abroad were made for holiday purposes. Of these, around a half (1.2 million) were on a package holiday whilst the rest travelled independently. There were 800,000 (21%) visits abroad to visit friends or relatives and 397,000 visits abroad for business purposes (10%). ( Table 11.24)

2.27 Over 75% (2.9 million) of Scottish residents' visits abroad were made to EU countries and visits to other European areas totalled 50,000 (1%). Visits to Canada and the USA together totalled about 365,000 (9%). ( Table 11.25)

2.28 The estimated number of visits abroad by Scottish residents increased from almost 3.1 million in 1999 to 3.9 million in 2009, a rise of 28%. There were large percentage increases for most of the main purposes of visit, and for each of the main areas visited. One should not read too much into some of the apparent year-to-year changes, which may be due to sampling variability. ( Table 11.26)

Transport Model for Scotland

2.29 Some information on travel between different parts of Scotland is available from the Transport Model for Scotland ( TMfS), which covers the area, broadly, from the Borders, through Perth and Dundee, stretching North East to Aberdeen and the surrounding area. The base year of TMfS is 2007.

2.30 It is estimated that, on an average weekday in 2007, 5 million person-trips were made by car, bus or train across the boundaries of one or more of the zones which are within the area covered by the TMfS. Two fifths of these trips were within Glasgow and Strathclyde (excluding Ayrshire), a fifth were within Edinburgh and the Lothians, and 10% were within Aberdeen and the North East. Only 12% of trips were between different TMfS sectors, with the largest such flows being roughly 52,000 person trips in each direction between Glasgow/Strathclyde and Ayrshire; around 42,000 person-trips each way between Glasgow/Strathclyde and Edinburgh/Lothians; about 41,000 person trips each way between Glasgow/Strathclyde and Central; and another 31,000 or so person-trips each way between Edinburgh/Lothians and Central. The numbers travelling between the area covered by the TMfS and elsewhere in Scotland are estimated to be around 236,000 each way per weekday. ( Table 11.27)

2.31 Of the 5 million inter-zonal person trips per weekday it is estimated that 4.2 million were by car. These accounted for over four-fifths of the total, and the main features of the pattern of trips by car were similar to (but smaller than) those described in the previous paragraph. There were also an estimated 0.9 million inter-zonal person-trips by bus or train per weekday. Two fifths of these were within Glasgow/Strathclyde, and about 20% were within Edinburgh/Lothians. The only flow between different TMfS sectors which involved as many as 11,000 bus or train passengers each way per weekday was between Glasgow/Strathclyde and Ayrshire. ( Table 11.27)

2.32 There was an average of almost 4.2 million trips per weekday by cars and goods vehicles. One third were within Glasgow/Strathclyde, and a sixth were within Edinburgh/Lothians: in total, 87% were within TMfS sectors. The largest flows between areas were around 45,000 vehicles each way per weekday between Glasgow/Strathclyde and Ayrshire, and about 38,000 vehicles each way per weekday between Glasgow/Strathclyde and Edinburgh/Lothian. ( Table 11.27)

2.33 The TMfS also produces estimates of the number of trips which are made by car, bus or train across the border with England. These suggest that, on an average weekday, around 8,000 people travel each way between Scotland and places in Yorkshire and South East England, about 5,000 travel each way between Scotland and places in Northumberland, and over 6,000 people travel to and from South West England and Wales. ( Table 11.28)

Concessionary Travel

2.34 158 million passenger journeys were made under all types of concessionary fare schemes in 2009-10, 3% less than in 2008-09. Concessionary travel schemes have varied over the years: a national minimum standard of free off-peak local bus travel for elderly and disabled people in Scotland was introduced from 30 September 2002, The scheme was extended to men aged 60-64 from 1 April 2003. In 2006 this was superseded by the introduction of the National Concessionary Travel Scheme for the elderly and disabled which allowed free bus travel across Scotland. Including the young persons scheme bus travel accounted for 152 million passenger journeys (97% of the total) in 2009-10. ( Table 11.29)

2.35 In 2009 Traveline Scotland received 613,000 telephone calls which was 4% less than the previous year. Its Web site recorded 3.2 million hits in 2009, an increase of 97% on the previous year. ( Table 11.30).

3. Notes and Definitions

National Travel Survey ( NTS) [ Tables 11.1 - 11.9]

3.1 The averages given in the tables are averages per head of population, and they will vary greatly from person to person: for example, there will be many people who do not travel on business at all, and others who travel thousands of miles on business.

3.2 A trip is defined as a one-way course of travel having a single main purpose. Outward and return halves of a return trip are treated as two separate trips. If a single course of travel involves a mid-way change of purpose then it is split into two trips (but trivial subsidiary purposes, such as a stop en route to buy a newspaper, are disregarded).

3.3 Main mode of transport: the mode that was used for the longest stage of the trip, where a trip involves more than one mode of transport (e.g. a bus and then a train). In the text, references to car trips include a few by van and lorry.

3.4 Length of a trip: the distance actually covered by the traveller, as reported by the traveller and not the distance as the crow flies.

3.5 Other personal business: includes - e.g. - trips to the bank, doctor, hairdresser, library and church.

3.6 Sampling variability: Because the NTS's Scottish sample is small (see section 4.1), its results may be affected by large percentage sampling errors. Chapter 8 of the NTS Technical Report 2000 provides information about the possible scale of the sampling errors for the survey's estimates for the three-year period 1998/2000. Tables on page 85 show the estimated per person per year averages, and their associated 95% confidence ranges, for different parts of Great Britain. The figures given for Scotland for 1998/2000 were:

• average trips per person per year - 1,058, with a 95% confidence range of +/- 56 trips (i.e. +/- 5%);
• average distance travelled per person per year - 7,210, with a 95% confidence range of +/- 583 miles (i.e. +/- 8%).

(These may have changed slightly following the Department for Transport's retrospective revision, in 2006, of the estimates back to 1995/1997 to use weighted results.)

Estimates based on smaller samples tend to be subject to larger sampling errors, all else being equal. The estimated numbers of trips made and distances travelled for some modes of transport could be subject to proportionately much greater sampling variability (because those modes were used by only a few people in the sample). Therefore, some of the apparent changes in some modes' figures in Table 11.2 may be due to sampling variability: for example, the apparent fluctuations in the surface rail figures (268 miles in 1995/97, 525 miles in 1998/2000, 339 miles in 2002/2003, 465 miles in 2004/2005 and 408 miles in 2005/2006) are inconsistent with the changes in the overall figures for rail passenger numbers for the same period. It is likely that the fluctuations in the NTS results reflect the inclusion (by random chance) in the sample of more rail users, or greater rail users, in some years than in other years. Similarly, some of the NTS results in other tables may be affected noticeably by sampling variability.

Scottish Household Survey ( SHS)

3.8 Annual net household income: this is the net income (i.e. after taxation and other deductions) which is brought into the household by the highest income householder and/or his/her spouse or partner, if there is one. It includes any contributions to the household finances made by other members of the household (eg dig money). In the case of households for which any of the main components of income were not known (for example, because of refusal to answer a question), the SHS contractors imputed the missing amounts, using information that was obtained from other households that appeared similar.

3.9 SHS urban / rural classification: the urban / rural classification shown in some tables was developed for use in analysing the results of the SHS. It is based on settlement size, and (for the less-populated areas) the estimated time that would be taken to drive to a settlement with a population of 10,000 or more. Each postcode in Scotland was classed as either urban or non-urban, then clumps of adjacent urban postcodes, which together contained more than a certain total number of addresses, were grouped together to form settlements. Six categories were then defined:

• Large urban areas - settlements with populations of 125,000 or more. These are around - but not the same as - Aberdeen, Dundee, Edinburgh and Glasgow. This category may (a) include areas outwith the boundaries of these four cities, in cases where a settlement extends into a neighbouring local authority, and (b) exclude some non-urban areas within the boundaries of these four cities.
• Other urban areas - other settlements of population 10,000 or more.
• Accessible small towns - settlements of between 3,000 and 9,999 people, which are within 30 minutes drive of a settlement of 10,000+ people.
• Remote small towns - settlements of between 3,000 and 9,999 people, which are not within 30 minutes drive of a settlement of 10,000+ people.
• Accessible rural areas - settlements of less than 3,000 people, which are within 30 minutes drive of a settlement of 10,000+ people.
• Remote rural areas - settlements of less than 3,000 people, which are not within 30 minutes drive of a settlement of 10,000+ people.

3.10 Full driving licence and frequency of driving: the SHS asks whether the person currently holds a full driving licence (car or motorcycle). For those who are said to hold a licence, the SHS asks how often the person drives nowadays. The interviewer records whichever of the categories shown in the table is the most appropriate, in the light of the answer. Prior to April 2003, these questions were asked of the head of the household, or his or her spouse/partner, about each adult member of the household. Since April 2003, these questions have been asked of a randomly-selected adult member of the household about themselves. Hence, results for previous years may not be entirely comparable with results for 2003 onwards.

3.11 Frequency of walking: the SHS asks on how many of the last seven days the person made a trip of more than quarter of a mile by foot. The interviewer asks about walking for the purpose of going somewhere, such as work, shopping or to visit friends. The interviewer then asks about walking just for the pleasure of walking or to keep fit or to walk the dog.

3.12 Frequency of cycling: the SHS asks on how many of the last seven days the person made a trip of more than quarter of a mile by bicycle. The interviewer asks about cycling for the purpose of going somewhere, such as work, shopping or to visit friends. The interviewer then asks about cycling just for the pleasure or to keep fit.

International Passenger Survey

3.14 The International Passenger Survey is designed to be representative of all people travelling in and out of the UK in terms of: the usage of air, sea and tunnel; UK residents going abroad and foreign residents coming to the UK; different types of traveller (e.g. holiday, business, etc); and travel to and from different parts of the world. However, it is not designed to produce results which are representative for different regions of residence within the UK. While the survey's procedures should not lead to any major bias in the estimates for Scottish residents, the sample-based nature of the survey may result in their being over-represented in the survey in some years, and under-represented in other years.

3.15 Visits abroad: The figures include all tourists who make trips which last no more than a year, those travelling to Eire have been included in the IPS since 1999.

3.16 Miscellaneous and other purposes: includes visits for study, to attend sporting events, for shopping, health, religious or other purposes, and multi-purpose visits for which no one purpose predominates.

3.17 Area visited: in cases where two or more countries are visited, a person is counted on the basis of the one country in which he or she stayed for the longest time.

Inter-zonal trips made on an average weekday - the Transport Model for Scotland ( TMfS)

3.18 These are the estimated annual average numbers of trips made per weekday between or within the areas shown, using the specified modes of transport (for example, they do not include trips made by foot, by bicycle, or by motorcycle). The figures represent the estimated total flows over the whole 24 hours of an average weekday. A return journey, from A to B and back again, on the same day, would be counted as two trips: one from A to B and one from B to A.

3.19 The figures are estimates of the numbers of inter-zonal trips - i.e. trips which cross the boundary of at least one of the zones used in the Transport Model for Scotland ( TMfS). The zones used in the model are constructed by amalgamating Population Census output areas. The model's zones vary in size from area to area, depending on factors such as the size and density of the population and the nature of the transport network that the model must represent. As a result, there is no simple definition of a zone. Some Council areas have many zones (e.g. there are 180 in Edinburgh, and 239 in Glasgow); others have only a few (e.g. there are 10 in East Lothian and 11 Midlothian and 21 in West Lothian). It follows that a trip of a particular length will be more likely to be counted as an inter-zonal trip if it is in (say) Edinburgh than if it is in (say) East Lothian.

3.20 Person trips relate to the number of people travelling by the specified modes of transport, and vehicle trips to the numbers of vehicles going between the specified areas. Thus, for example, if a car containing two people goes from A to B, it is counted as two person trips and one vehicle trip.

3.21 The areas identified in the table are sectors within the TMfS. These correspond broadly (but not necessarily exactly) to the areas of the similarly-named former Regions and/or current Councils. Some of these sectors do not contain many TMfS zones - for example, the Borders sector contains 11 zones, and the Perth & Kinross sector contains 23 zones. All else being equal, the larger the zones are within a sector, the smaller the proportion of the trips within the sector that will be treated as inter-zonal trips - and, hence, the smaller the proportion that will be represented within the model.

3.22 Elsewhere in Scotland refers to those parts of Scotland which are outwith the TMfS model area: broadly, Arran, Argyll & Bute, Highland, Moray, Orkney, Shetland and the Western Isles. The model does not hold information regarding trips which are wholly outwith its model area, such as a trip between Inverness and Dingwall, which would be wholly within the elsewhere in Scotland area.

3.23 The estimated average number of trips originating in an area usually differs from the estimated number with a destination in that area - for example, compare the estimates of 869,000 person trips with a destination in Edinburgh & Lothians and 868,000 trips originating in Edinburgh & Lothians. This is because the estimation process (which is described in section 4) is mainly based upon survey data covering the 7 a.m. to 7 p.m. period, and cannot take full account of trips which involve returning later in the evening. Therefore, the TMfS-based estimates indicate broadly the levels of flows within Scotland, but do not provide precise measures.

3.24 The model's estimates of the number of cross-border trips by bus and train may not be particularly reliable, because of the way that they are produced - see section 4.

4. Sources

4.1 Travel (within GB) by Scottish residents ( Tables 11.1 to 11.9, and 11.22)

4.1.1 The National Travel Survey ( NTS) collects travel diary details from a sample of households across Great Britain and includes travel for all private purposes. Trips in the course of work are included if the main reason for the journey is for the traveller to reach the destination whereas travel in the course of work (to convey passengers or to deliver goods) is excluded (e.g. by bus drivers, lorry drivers and postmen). Trips off the public highway, such as country walks, are excluded.

4.1.2 Prior to 2002, the NTS was not designed to provide reliable estimates for Scotland for single years: the sample included only a few hundred Scottish households each year. Therefore, the samples for a number of years had to be combined in order to produce Scottish results, and even they could be subject to considerable sampling variability. In 2002, the NTS's sample size was increased greatly, enabling the production of results for individual calendar years with effect from 2002. However, the sample size was less in 2002 than in the previous three years taken together, and therefore the results for 2002 alone could be subject to greater sampling variability than those for 1999/2001 taken together. The tables therefore give results for the two-year periods 2002/2003, 2004/2005, 2006/2007 and 2008/2009 as they should be more reliable, being based on a larger sample. Section 3.6 provides some information about sampling variability.

4.1.3 In 2006, the Department for Transport (DfT) revised retrospectively NTS results for 1995/1997 onwards, following its introduction of a method of weighting the data to adjust for differential response rates among different sections of the population (in order to reduce the effects of non-response bias) and to adjust for the drop off in the reporting of journeys during the course of the seven days covered by the NTS Travel Diary (which is done separately for each journey purpose, using their weighted total numbers, assuming that the reporting on the first day of the travel week is the most accurate). In order to allow analysis of trends in recent years, DfT developed retrospectively weighting factors for the NTS data back to 1995. Greater weight was given to respondents from sub-groups which had lower response rates. The weighting process was also used to adjust the balance of the sample to correspond to the population estimates by age and sex for Scotland and other parts of Great Britain. The use of the weights increased the overall number of trips and average distance travelled per person by 4-5 percent for GB as a whole.

4.2 Frequencies of driving, walking and cycling; and usual main methods of travel to school and travel to work ( Tables 11.10 to 11.12 and 11.19 to 11.21)

4.2.1 Information on these and some other transport-related topics is collected by the Scottish Household Survey, which started in February 1999. The SHS collects information on a wide range of topics, to allow exploration of the relationships between different sets of variables. Interviewing takes place throughout the year.

4.2.2 The SHS is a survey of private households. For the purposes of the survey, a household is defined as one person or a group of people living in accommodation as their only or main residence and either sharing at least one meal a day or sharing the living accommodation. A student's term-time address is taken as his/her main residence, in order that he/she is counted where he/she lives for most of the year. The sample was drawn from the Small User file of the Postcode Address File ( PAF) which does not include many nurses' homes, student halls of residence, hostels for the homeless, other communal establishments, mobile homes, and sites for travelling people.

4.2.3 Each year, SHS interviews are conducted with a randomly-chosen sample of (on average) over 15,000 households across Scotland. Within each Council area, the sample is stratified using a geo-demographic indicator in order that it will be representative across that Council's area. A higher sampling fraction is used in the areas of the Councils with the smallest populations, in order that (in each two-year period) there is a minimum of 550 household interviews per Council. The results are then reweighted so that they will be representative of Scotland as a whole.

4.2.4 The SHS interview is conducted in two parts. The first part is with the highest income householder, or his/her spouse/partner (if any), who answers questions about the household and its members. This provides household members' age and gender , and the annual net household income. Prior to April 2003, it included questions about the type of driving licence (if any) held by each adult member of the household, and the frequency of driving. Main method of travel to school was also collected (for one randomly-chosen schoolchild member of the household). As the information is collected for one schoolchild per household, proportionately greater weight is given to cases with greater numbers of schoolchildren in the household.

4.2.5 The second part of the SHS aims to obtain results which are representative of Scottish adults by interviewing a randomly-chosen adult (aged 16+) member of the household (who may happen to be the person who answered the questions in the first part of the interview - for example, this is always the case for single pensioner households). This part has fewer respondents as not all randomly-chosen adults are available. Information on the frequency of walking, place of work , usual method of travel to work etc are collected Questions are also asked about journeys made on the previous day (the Travel Diary). These include the start and end times of each stage of the journey, the mode of transport used, the purpose of the journey, and experiences of congestion. As one adult is interviewed per household, proportionately greater weight is given to cases with greater numbers of adults in the household. For the Travel Diary questions, further weighting is given according to the day of the week and the economic status of the adult.

4.2.6 Although the SHS's sample is chosen at random, respondents will not necessarily be a representative cross-section of the people of Scotland. E.g. the sample could include disproportionate numbers of certain types of people, in which case the survey's results would be affected. In general, the smaller the sample from which an estimate is produced, the greater the likelihood that the estimate could be misleading. SHS publications (see sections 5.3 and 5.4) provide examples of the 95% confidence limits for estimates of a range of percentages calculated from sub-samples of a range of sizes.

4.2.7 The above information relates only to sampling variability. The survey's results could also be affected by non-contact / non-response bias: the characteristics of the (roughly) one-third of households who should have been in the survey but who could not be contacted, or who refused to take part, could differ markedly from those of the people who were interviewed. If that is the case, the SHS's results will not be representative of the whole population. Without knowing the true values (for the population as a whole) of some quantities, one cannot be sure about the extent of any such biases in the SHS. However, comparison of SHS results with information from other sources suggests that they are broadly representative of the overall Scottish population, and therefore that any non-contact or non-response biases are not large overall. Of course, such biases could be more significant for certain sub-groups of the population. In addition, because it is a survey of private households, the SHS does not cover some sections of the population - for example, it does not collect information about many students in halls of residence. The SHS technical reports (see section 5.4) provide more information on these matters.

4.3 Travel to work ( Tables 11.16 to 11.18)

4.3.1 The information about the usual means of travel to work and the time taken to travel to the usual place of work shown in tables 11.16 and 11.17 is obtained from the Labour Force Survey using questions which have been included in those survey interviews which have been conducted in the Autumn each year since 1992. The tables include the self-employed, those on Government training schemes and unpaid family workers as well as employees, but exclude those working at home, and those whose workplace or mode of transport to work was not known. The LFS is a household survey covering 60,000 households each quarter in GB, and about 6,000 households per quarter in Scotland.

4.3.2 Table 11.18 provides some Census of Population information about travel to work. There have been some changes in the categories used - for example, the 1966 Census had a category described as none which was included in the 1971 Census under its On foot and none category; the 1971 Census had a category described as Public Transport which was separate from the categories for Train and Bus; and the 1966 and 1971 Census travel to work figures did not identify separately those who were working at home, so they are included in the figures for those years. However, the effect of such differences on the statistics will be small compared to the scale of the changes in the shares of the main modes of travel.

4.3.3 Information about travel to work is also collected by the SHS (see section 4.2 above), which is the source for tables 11.18 and 11.22.

4.4 Scottish residents' visits abroad ( Tables 11.26 to 11.28)

4.4.1 This information is collected by the International Passenger Survey ( IPS), from a sample of passengers returning to the UK by the principal air, sea and tunnel routes (excluding some routes which are too small in volume or which are too expensive to be covered). Travellers passing through passport control during the day are randomly selected for interview (interviewing is suspended at night). A weighting procedure takes account of the non-sampled routes and time periods. For example, the figures for certain airports are uplifted to take account of the passenger numbers at the other UK airports which are not covered by the survey. Prior to 2005, Edinburgh and Glasgow were the only Scottish airports at which interviewing took place. Prestwick airport was added to the survey in 2005 and Aberdeen has been collected since 2009. These are uplifted to take account of the non sampled airports. Rosyth was included in quarters 2, 3 and 4 of 2007 and quarters 2 & 3 of 2008.

4.4.2 The figures in the tables are based on interviews with Scottish residents who returned to the UK. This is the Office for National Statistics' standard practice for producing such estimates, as it can then also analyse other information that is collected in the interviews (such as the amount that people say that they spent while on holiday).

4.4.3 The survey covers both adults and children, and is voluntary - for example, the response rate was 80% in 2003, and the results reported in these tables for that year are based upon interviews with about 2,000 Scottish residents.

4.4.4 The IPS data used in the tables are adjusted to take account of the fact that not all people respond to questions regarding area of residence. This means that tables produced by area of residence will not always exactly match other published data regarding trips abroad by UK residents.

4.5 Trips made on an average weekday (Table 11.29 and 11.30)

4.5.1 These figures were provided using the Transport Model for Scotland 2007. This model covers the Scottish Strategic Transport Network, and also includes representation of travel patterns between Scotland and England. This covers the areas from the Borders, through Perth and Dundee, stretching North East to Aberdeen and the surrounding area, in which lives roughly 95% of the population of Scotland.

4.5.2 The area covered by the model is divided into 720 zones. The model uses planning data for each zone (e.g. population, number of households, car ownership, employment, number of employed residents) to calculate the number of trips that would be expected to be generated. It also uses information collected by traffic counts, roadside interviews and surveys of passengers on public transport. The information collected and used to develop the model started in 2002 and continued through to 2007, which is the base year. TMfS also uses information from other sources, such as 'donor' models (such as the Strathclyde Integrated Transport Model), the 2001 Census of Population and the Scottish Household Survey (which has been conducted continuously since February 1999). Data collected in other years were factored to represent the base year. The quality and coverage of the data that are held within the TMfS vary between different areas and different parts of the transport network. This is the result of the historical interest in the movement of people and goods between various points on the transport network, and the resultant availability of data. However, the base information used to develop TMfS:07 is more robust and comprehensive than that used in former versions of the national model.

4.5.3 The pattern of travel movements is held in a series of trip matrices covering the morning peak period, the evening peak period and the intervening off-peak period. Taken together, these matrices can be combined to provide a matrix reflecting trip movements during the period 7 a.m. to 7 p.m. on a typical weekday. Daily, monthly and annual averages can then be derived by grossing-up these figures using time series data sources. The resulting expected flows around the transport network are then calibrated and validated for each modelled time period using information about the actual numbers of trips that were made on particular routes.

4.5.4 Applying the calibration and validation process to the expected numbers of generated trips calculated by the model produces estimates of the numbers of trips which are consistent with the observed traffic counts and the results of surveys and interviews. The estimated numbers of trips for the areas shown in the table were then produced by aggregating the estimated numbers of trips for the relevant zones.

4.5.5 The model's estimates of the numbers of people travelling by bus and train across the border with England are less reliable because it uses its standard set of public transport factors to gross up the cross-border passenger numbers obtained (e.g.) from surveys and passenger counts which were carried out at certain times on certain days. Because local bus services account for the vast majority of public transport in Scotland, the model's standard public transport grossing-up factors mainly reflect the pattern of local bus passenger usage - so applying these factors to the data for cross-border bus and train traffic may not take proper account of the different patterns of such traffic.

4.6 Passenger journeys made under concessionary fare schemes (Table 11.31)

4.6.1 The figures for the Strathclyde Concessionary Travel scheme were supplied by Strathclyde Partnership for Transport ( SPT); the figures for other schemes were collected from Transport Scotland (national schemes) and from local authorities using the Local Financial Returns form LFR5.

4.6.2 The National Concessionary Travel bus scheme was introduced on 1st April 2006, which allows elderly and disabled free travel on all scheduled bus services in Scotland. This is administered by Transport Scotland and replaced any local bus schemes. The Young People's Concessionary bus Travel Scheme started in 8 January 2007, aimed at 16 to 18 year olds (inclusive) and full time volunteers (aged under 26).

4.6.2 Local authorities were asked to provide numbers of passenger journeys on the same basis as the expenditure on concessionary fares that they report in the LFR5. This relates to concessionary fares for elderly people, for people with visual or other disabilities, and for children (but exclude school transport).

4.6.3 SPT was able to provide passenger numbers from its records for the Strathclyde Concessionary Travel scheme for several years; figures for the passenger numbers for other schemes are only available for 2000-01 onwards because that was the first year for which that information was requested from local authorities using the LFR forms.

5. Further Information

5.1 National Travel Survey statistics for Scotland are available on the SG website. This includes webtables and an accompanying background note. The National Travel Survey is also described in the Department for Transport website.
www.scotland.gov.uk/Topics/Statistics/Browse/Transport-Travel/PubTravScotRes
www.dft.gov.uk/pgr/statistics/datatablespublications/nts/

5.2 National Travel Survey statistics: nationaltravelsurvey@dft.gsi.gov.uk

5.3 Labour Force Survey - lfs.dataservice@ons.gsi.gov.uk

5.3 There are a number of transport specific publications on the Scottish Household Survey available at:
www.scotland.gov.uk/Topics/Statistics/Browse/Transport-Travel/Publications

5.4 SHS publications include Scotland's People, a detailed Annual Report and can be accessed at: www.scotland.gov.uk/Topics/Statistics/16002/Publications Enquiries regarding the Scottish Household Survey should be directed to the SHS Project Manager: Nic Krzyzanowski (tel: 0131 244 0824).

5.6 Enquiries regarding the International Passenger Survey should be directed to Josh Lovegrove of the Office for National Statistics (tel: 020 7533 5765).

5.7 Further information or guidance on the detailed application of the Transport Model for Scotland can be obtained from Alison Irvine, Transport Scotland Strategy and Investment (tel: 0141 272 7571).

5.8 Further information about the numbers of passenger journeys made under concessionary fare schemes can be obtained from Maureen Fisher in Transport Scotland (tel: 0131 272 7533).

5.9 Further information about the number of telephone calls and Web site hits for Traveline Scotland can be obtained from Peter J Cullen, Travel Information Manager, Trunk Roads and Network Management, Transport Scotland, (tel: 0141 272 7381).