2.2.2. Objective job characteristics
Objective job characteristics (including job characteristics and organizational context variables from the review of
Holtom et al., 2008) are our second group of explanatory variables. First we control for the different subsectors using a
dummy for special regular services and occasional services (with public transport as reference category). Since some drivers
are active in different subsectors, the subsector variable refers to the activity the drivers exercises most of the time. Furthermore,
as Sousa-Poza and Henneberger (2004) point to more job security as a ‘universal’ determinant of lower turnover intentions
(and thus also for the transport sector), we included a dummy for an indefinite contract (reference is a fixed term or day
contract). The dynamic study of two carriers in the US of Suzuki et al. (2009) suggest operational work variables (such as
weekly miles) are predictors of drivers’ turnover intentions. Therefor we entered the number of hours worked per week,
number of times working on non-conventional hours per month, and dummies for getting informed on work schedules
changes (reference is no changes in work schedule) as explanatory variables in our model. Haines et al. (2010) found that
employer-provided training increases voluntary turnover in Canada. Our data also has information about training but these
variables were not significant for this specific sector and left out the presented results in Section 4.