The relevance of commute distance and time in locational choices

Commute is a spatially-related process underlying the labor market (Sang, O'Kelly and Kwan 2011: 906). It is the circulation space in the city, connecting production space (employment) and social space (housing) (Scott and Storper 2014: 8). Accordingly, the urban structure in terms of the distribution of housing and employment affects the length of commute trip. In addition, from a micro individual perspective, personal behavioral factors also play important roles in commute distance (Boussauw, Neutens and Wiltox 2012: 690). This section will introduce the commute distance and time firstly from a macro-spatial perspective and secondly from a micro-behavioral perspective.

2.4.1 Commute patterns in relation to urban structure, as well as the distribution and location of residences and workplaces

Commuting distance is strongly influenced by the urban structure in terms of aggregated distribution of residences and workplaces. Naess (2007) comes up with three scenarios of urban structure in terms of residence and workplace distribution, and the associated commuting distance (Naess 2007). When workplaces are more centralized than residences, the inner-city residents usually have a short commute distance, whereas the employees in the inner city have a longer commute distance. When workplaces and residences are both concentrated in the inner part rather than the outer part of the metropolitan area, it contributes considerably to short commuting distance among inner-city residents as well as employees who work in the inner city. When the downtown area is an approximate point of gravity for workplaces and residences (simultaneously a node in the transport network), it contributes to some extent to shorter commuting distance among inner-city residents and employees whose workplaces are in the inner-inner-city (Naess 2007: 155).

There is also research on the relation between specific workplace or residence location and the length of commute. The empirical study in Copenhagen, which has a monocentric spatial structure, suggests that commuting distance in general increases with the distance of the residence to the downtown area (Wang 2000; Naess 2007: 154). In contrast, there is no clear trend discernable in distance of workplace to downtown area and commute distance. The commute distance firstly increases and then decreases with the increase of the distance between workplace and the downtown area (Naess 2007: 154). The decreasing trend might relate to the phenomena that the less skilled workforce are frequently employed in places that are closer to their residence than downtown areas.

2.4.2 Theories on commute distance and time

Regarding the role of commute in the location choices from a behavioral perspective, there are two strands of argument. On the one hand, people’s desire for residence and workplace proximity is underestimated and the ability of households to modify the situation of long commute is greater than researchers expected previously. Many households seem to search for low commuting costs, even if they do not limit themselves to the alternative with the least commuting cost (Korsu 2012: 1966). In most cases, residential or workplace changes will shorten the commute distance of at least one worker in two-worker households. Moreover, the theory of constant time budget assumes that a rational individual would Aggregated urban

21 periodically relocate their workplace and residence, or alter their

commute behaviors in order to maintain a reasonable commuting time (Kung et al. 2014: 12; van Ommeren, Rietveld and Nijkamp 2000). This corresponds to the fact that urban commuting time has remained stable or increased only slightly in past three decades in spite of continuous population growth and increases in commuting distance and congestion (Gordon, Richardson and Jun 1991; Levinson and Kumar 1994; Crane and Chatman 2003; Kim 2008).

On the other hand, the commute time or distance is not that absolute.

Instead, people are willing to tolerate long commutes for better residential and employment conditions. As long as the time is kept under the threshold level, there will be no direct motivations for further adjustments or changes. Collectively, empirical studies suggest that the tolerable commute time for one-way trip is in the range of 30min to 45min (Levinson and Wu 2005: 189). According to this theory, commute functions as a lubricant for labor market flexibility and residential adjustment, which permits the change of one of residence and workplace locations and keeps the other unaffected (Parr 2014). This explains why the commuting space expands with commuter trip lengths and the share of long commutes has increased year on year in European and North American metropolitan areas (Boussauw, Neutens and Wiltox 2012: 690;

Banister 1997; Siedentop and Fina 2010; Guth et al. 2011).

The choice of commute is a trade-off between the benefits of better access to the job with the costs associated with the commute trip (Handy 2005). A greater commute tolerance is expected for a job better matching one’s skills and offering better career prospects. Indeed, Burger, van der Knaap and Wall (2014) observed in the Randstad region that the commuting patterns of highly educated employees are regional wide, whereas less well-educated employees’ commuting patterns are local scale oriented (Burger, van der Knaap and Wall 2014). Similarly, high-income individuals are more likely to be less sensitive to long commute distance compared to low-income workers due to the affordability of commute costs (Vovsha et al. 2012: 19; Naess 2007: 152), which is consistent with the finding of Li (2010) that commuting distance in general increases with income and occupational status (Li 2010). In addition, other socio-demographic situations also influence commute. Females typically have shorter commute time (Modarres 2011: 1199). The number of workers per household and the property status of the residence also have an influence on the commute distance (Boussauw, Neutens and Wiltox 2012: 690; Wang 2000). Last but not least, the employment conditions also generate effects on commute. Workers with the option of

Individuals have a certain tolerance for commute

Commute varies among different groups of population

home-office and the availability of a company car tend to have longer commute distances (Frenkel, Bendit and Kaplan 2014, 2013b; Saxena and Mokhtarian 1997; Tayyaran and Khan 2003).

2.5 Choice of commute mode: impact of built