Tools for transport planning with an emphasis on spatial
    transport data and non-motorized modes.
    The package was originally developed to support the 'Propensity to Cycle Tool', a publicly available strategic cycle network planning tool
    (Lovelace et al. 2017) <doi:10.5198/jtlu.2016.862>, but has since been
    extended to support public transport routing and accessibility analysis
    (Moreno-Monroy et al. 2017) <doi:10.1016/j.jtrangeo.2017.08.012> and
    routing with locally hosted routing engines such as 'OSRM'
    (Lowans et al. 2023) <doi:10.1016/j.enconman.2023.117337>.
    The main functions are for creating and manipulating geographic "desire
    lines" from origin-destination (OD) data (building on the 'od'
    package); calculating routes on the transport network locally and via
    interfaces to routing services such as <https://cyclestreets.net/>
    (Desjardins et al. 2021) <doi:10.1007/s11116-021-10197-1>;
    and calculating route segment attributes such as bearing. The package
    implements the 'travel flow aggregration' method described in Morgan
    and Lovelace (2020) <doi:10.1177/2399808320942779> and the
    'OD jittering' method described in Lovelace et al. (2022)
    <doi:10.32866/001c.33873>.
    Further information on the package's aim and scope can be found in the
    vignettes and in a paper in the R Journal (Lovelace and Ellison 2018)
    <doi:10.32614/RJ-2018-053>, and in a paper outlining the landscape of
    open source software for geographic methods in transport planning
    (Lovelace, 2021) <doi:10.1007/s10109-020-00342-2>.

Utilities to estimate parameters of the models with survival functions 
             induced by stochastic covariates. Miscellaneous functions for data preparation 
             and simulation are also provided. For more information, see: 
             (i)"Stochastic model for analysis of longitudinal data on aging and mortality" 
             by Yashin A. et al. (2007), 
             Mathematical Biosciences, 208(2), 538-551, <DOI:10.1016/j.mbs.2006.11.006>;
             (ii) "Health decline, aging and mortality: how are they related?" 
             by Yashin A. et al. (2007), 
             Biogerontology 8(3), 291(302), <DOI:10.1007/s10522-006-9073-3>.