Proposal to resolve a longstanding inconsistency in UN R125 between the lower datum point (§5.1.1.3, set at 5°) and the obstruction requirement (§5.1.3, set at 4°), by aligning the lower datum point to 4° while retaining upper and lateral aspects of §5.1.1. unchanged. The 5° datum point has never been used for any technical requirements beyond serving as a reference point, while the 4° obstruction requirement has prior precedent. As this is a vehicle rather than component requirement, the datum point is also proposed for deletion from UN R43, retaining it solely in UN R125.