l n ( I N F R A R O A D r , t ) = − 2.539 + 0.483 ∗ l n ( G D P P r , t L A N D A R E A r , t ) + 0.183 ∗ l n ( P O P r , t L A N D A R E A r , t − 0.102 ∗ l n ( L A N D A R E A r , t ) {\displaystyle ln(INFRAROAD_{r,t})=-2.539+0.483*ln({\frac {GDPP_{r,t}}{LANDAREA_{r,t}}})+0.183*ln({\frac {POP_{r,t}}{LANDAREA_{r,t}}}-0.102*ln(LANDAREA_{r,t})}
