Minibus Rerouting and Jurisdictional Fragmentation in Nairobi's Urban Periphery: A Spatial Regression Discontinuity Estimate of Commute Burdens on Low-Wage Employment Access

Nairobi's outer estates face repeated minibus diversions where Nairobi City County meets Kiambu, Machakos and Kajiado jurisdictions, yet planning debate seldom separates administrative discontinuity from underlying terrain and road impassability. It proposes a Peripheral Commute Burden Composite Spatial Index integrating Slope, Drainage density, Rainfall intensity, Land cover, Soil permeability, Elevation and Distance to channels, coupled to a spatial regression discontinuity design at fragmented county boundaries to isolate boundary-induced change in access to low-wage employment. The framework specifies spatial units, weighting, bandwidth choice and falsification logic without claiming completed inference, and it clarifies the conditions under which fragmentation would constitute a distinct burden rather than a proxy for poor terrain.