BOD- (P) Objective tests are used
DEV- this requires C to show D didnt meet the reasonable person standard, regardless of D's awareness
In Nettleship v Weston - D was held to standard of ordinary driver, even without driving license. This ensures consistent assessments are used.
E- H/e while subjective tests seem fair to D, the objective standard balances C rights against D risks without allowances for certain. e.g. Age - Mullin