, ▁primarily ▁agricult ural ▁land , ▁that ▁takes ▁advantage ▁of ▁the ▁fert ile ▁cl ay ▁soil ▁depos ited ▁throughout ▁the ▁region . ▁The ▁main ▁river ▁through ▁the ▁region ▁is ▁the ▁Th ames ▁River , ▁which ▁dra ins ▁the ▁second ▁largest ▁waters hed ▁in ▁southern ▁Ontario ▁and ▁largely ▁influ ences ▁the ▁land ▁use ▁surrounding ▁the ▁highway ; ▁It ▁par alle ls ▁the ▁route ▁to ▁the ▁north ▁between ▁T il bury ▁and ▁Wood stock . ▁ ▁Near ▁T il bury , ▁Highway   4 0 1 ▁los es ▁its ▁tall ▁wall ▁median ▁bar rier ▁and ▁narrow s ▁to ▁four ▁lan es , ▁following ▁lot ▁lines ▁laid ▁between ▁con cess ion ▁roads ▁in ▁a ▁plan ▁designed ▁to ▁limit ▁damage ▁to ▁the ▁sensitive ▁agricult ural ▁lands ▁through ▁which ▁the ▁highway ▁runs . ▁Here ▁the ▁highway ' s ▁flat ▁and ▁straight ▁route ▁is ▁not orious ▁for ▁leading ▁to ▁driver ▁in att ention . ▁The ▁section ▁from ▁W inds or ▁to ▁London ▁( es pecially ▁west ▁of ▁T il bury ) ▁has ▁become ▁known ▁for ▁dead ly ▁car ▁acc idents ▁and ▁p ile - ups , ▁ear ning ▁it ▁the ▁nick name ▁Car n age ▁Al ley . ▁As ▁the ▁highway ▁approaches ▁London , ▁Highway   4 0 2 ▁mer ges ▁in , ▁resulting ▁in ▁a ▁six - lane ▁cross - section . ▁Within ▁London , ▁it ▁intersect s ▁the ▁city ' s ▁two ▁municipal ▁express ways , ▁High bury ▁Avenue ▁and ▁the ▁V eter ans ▁Memorial ▁Park way . ▁ ▁The ▁section ▁between ▁London ▁and ▁Wood stock ▁generally