Road transport has been a major contributor to New Zealand's increasing rate of C[O.sub.2] emissions over the past 15 years. New Zealand Travel Survey (NZTS) data show that 29% of the kilometres travelled by households are for social and recreational purposes. These trips are less amenable to the travel demand management strategies applied in work and school settings (such as increasing public transport, parking restrictions and travel plans) because they occur at all times of the day and all days of the week, and trips are taken to an unlimited number of destinations. To understand the characteristics of social and recreational travel, an analysis of the destinations of the 18,299 social and recreational trips recorded in the 2003-2006 NZTS was undertaken. Transport mode use for the most common trip destinations was compared and differences in trip patterns by gender, age, ethnicity and neighbourhood deprivation were examined. It was found that trips to visit family and friends and recreational trips to open spaces such as beaches, lakes and parks are the most common destination categories and those least often made on foot. The potential and limitations of virtual mobility and urban design to reduce C[O.sub.2] emissions from household social and recreational travel are discussed.
As evidence of global climate change and its anthropogenic basis accumulates (HM Treasury 2006, IPCC 2007), sources of New Zealand's greenhouse gas emissions have come under increasing scrutiny. Strategies to reduce emissions and the likely social implications of decarbonisation policies are also being examined (Boston 2007, Chapman and Boston 2007).
In 2005 transport contributed 18% of New Zealand's C[O.sub.2]-equivalent (C[O.sub.2]-e) emissions and road transport represented 89% of these emissions (Ministry for the Environment 2007). A striking feature of transport emissions has been their rapid growth, with road transport emissions increasing 65% between 1990 and 2005. At this level road transport has been a major contributor to New Zealand's overall rate of emissions increase: 25% over the 15-year period (Ministry for the Environment 2007).
New Zealand has one of the highest rates of car ownership internationally, relatively low-density urban development and poor public transport infrastructure, all factors that have contributed to making us an auto-dependent nation. The same factors will make reducing C[O.sub.2] emissions from domestic travel particularly challenging. The trend in New Zealanders' transport behaviour has been one of increasing annual distances travelled by car (as both drivers and passengers) and decreasing distances using active transport modes (walking and cycling) (Ministry of Transport 2007a). A comparison of national annual estimates (NAEs) of the total distance driven by New Zealanders in the 1997/98 and 2003-06 household travel surveys indicates an increase of 16% between the surveys. In the same time period the population increased by 7%.
Social and recreational trips are a major component of domestic travel. Data from the 1997/98 survey showed that work-related trips (24%) and social and recreational trips (29%) made the highest contribution to the annual tally of kilometres travelled by vehicle drivers. (2) The significance of social and recreational travel is also underscored by data from the New Zealand Time Use Survey. An analysis of average minutes per day spent travelling for different purposes indicates that social and recreational travel consumes more time than work-related travel, for both men and women (Statistics New Zealand 2000). Women averaged 18 minutes a day travelling for social entertainment and sporting purposes and 12 minutes on labour-force participation. For men the equivalent times were 20 and 19 minutes, respectively.
Travel behaviour patterns, including mode use, differ depending on the purpose of a trip (Handy 1996). A comparison of mode use for work-related and social and recreational trips using 1997/98 survey data indicates that 72% of work-related trips were made as a vehicle driver compared to 38% of social and recreational trips; passenger trips comprised 7% of work-related trips and 35% of social and recreational trips; and walking trips were 15% of work and 22% of social and recreational trips (Land Transport Safety Authority 2000). Work-related trips are generally to a specific place, for a standard time period on set days of the week. Social and recreational trips are infinitely more flexible. They can occur at any time of the day, any day of the week and to an unlimited number of destinations.
Trips to work and school contribute to Monday to Friday peak-hour congestion so they have been extensively studied (Cairns et al. 2002). As a consequence, travel demand management (TDM) strategies, such as workplace and school travel plans, have been developed and are being implemented to ease congestion in larger urban areas (e.g. Auckland Regional Transport Authority 2007). By contrast, little attention has been given to understanding the characteristics of social and recreational travel. However, if a policy objective is to reduce C[O.sub.2] emissions, all kilometres travelled contribute to emissions irrespective of trip purpose. Social and recreational travel is often described as "discretionary" whereas work-related and education-related trips are cast as "essential" (Frank et al. 2007, Loukopoulos et al. 2006). However, this categorisation is at odds with the importance placed on social inclusion within social policy in New Zealand and elsewhere (Miller 2007, Spoonley et al. 2005, Statistics New Zealand 2006). Mobility enables individuals and households to meet needs, aspirations and obligations that involve participation in activities that occur beyond the home. A change in transport behaviour that restricts participation in various life domains can contribute to social exclusion (Lucas 2004). This relationship has been observed in local studies of the impacts of poor access to transport on the lives of older people and people with disabilities (Davey 2004, Human Rights Commission 2005). Maintaining social ties and networks requires investments of time, and face-to-face contact can seldom be entirely replaced by virtual contact (Loukopoulos et al. 2006).
There are few situations where the effect of withdrawing access to private vehicles on the travel behaviour of the broader population can be observed. A rare example was the introduction of the carless day scheme to New Zealand in 1979 in the face of fuel price and supply fluctuations. The strategies people adopted to maintain their household activities varied by trip purpose (Elliot et al. 1980). Work-related trips on a nominated carless day, 84% of which were undertaken by car prior to the introduction of carless days, continued to be taken primarily by car (62%), either through the use of an exempt or second car or by car sharing. Mode shift occurred mainly through car pooling (5% to 19%) and to a lesser extent by increased bus (2% to 7%), motorbike (2% to 7%) and bicycle (7% to 12%) use. Shopping trips, car-based for 88% of trips prior to the carless day scheme, also continued to be primarily a car-based activity (55%), with mode shift favouring bicycle (3% to 15%) and walking (9% to 20%).
The response to social and recreational trips was somewhat different. Again car use for these trips was high before (88%) and after the introduction of carless days (66%) through the use of a second car or car pooling, but there was scant evidence of mode shift. Rather, 33% of trips were postponed (Elliot et al. 1980). The authors concluded that "The absence of non car modes suggests that personal [equivalent to NZTS social and recreational categories] trips are strongly linked to car use, and that carless days may be having a significant social impact" (p. 23). Mode shift was most common for regular trips (work) and to destinations that were geographically proximate (shopping).
An individual's travel patterns can be described as a series of trajectories in time and space (Miller 2007). Time is allocated to activities such as work, home, shopping and recreation, as well as time to move between these activities, as they generally take place at different geographic locations. Transport modes and information and communication technologies are then used to trade time for space as we schedule at a personal or household level how we can participate in various activities. Everyone has a finite time budget: an amount of time to allocate to a range of activities over a day or week or other prescribed time period (Huisman 2005). A person with access to a private vehicle can expand their activity space and respond to opportunities in narrower time windows than a person reliant on walking or public transport. Space-time activity analysis has highlighted differences in activity patterns and constraints on activities for people of different gender, age, socio-economic status and life stage (Kwan 1999). In sprawling, auto-dependent urban environments and rural areas where activity locations are widespread, limited access to a car can result in spatio-temporal exclusion: an inability to participate in activities, obtain resources or benefit from opportunities (Miller 2007). Land-use changes that increase the dwelling density and decrease distances between work, home and play are strategies...