🗺️ A New Proxy for State Reach

Travel time to national and regional capitals is used as a proxy for local state capacity. Comprehensive panel data were constructed to capture how changes in physical access to state centers shaped development across Africa.

📊 How the Measure Was Mapped (1966–2016)

• A yearly 5 × 5 km grid covering African territory was created for 1966–2016.
• Time-varying data on roads and administrative boundaries were used to compute travel times to both national and regional capitals for every grid cell.

🔎 What Outcomes Were Tested

• Local education provision
• Infant mortality rates
• Nightlight emissions (as a proxy for economic activity)

📈 Key Findings

• Within the same location, decreases in travel times to capitals are robustly associated with better development outcomes.
• Shorter travel times correlate with improved education provision, lower infant mortality rates, and higher nightlight emissions.

⚖️ Why This Matters

• Provides a fine-grained, time-varying measure of state reach that advances measurement of state capacity.
• Connects changes in physical access to state centers with concrete improvements in human welfare, offering a clearer link between state infrastructure, administrative reach, and development outcomes.