McDonald v. The Queen, 98 DTC 2151, [1998] 4 CTC 2569 (TCC) -- summary under Subsection 6(2)

The taxpayer, who was employed as a safety manager, was required to attend on a daily basis various parks and recreational facilities in the greater Toronto area, in addition to attending from time-to-time at an office downtown. The taxpayer's travel between his home and the various park locations was found to be business use given that it was more efficient and cost effective for his employer for him to begin or end such trips at his home. Furthermore, even if such trips were treated as personal use so that they amounted to 15% of the total use of his car, 85% of the total distances travelled represented "substantially all" of such distances give the elasticity of the word "substantially".