▁the ▁East ▁Don ▁River ▁and ▁clim bs ▁toward ▁the ▁Don ▁Valley ▁Park way , ▁which ▁provides ▁access ▁to ▁dow nt own ▁Toronto ▁and ▁Highway   4 0 4 , ▁which ▁provides ▁access ▁to ▁the ▁sub ur bs ▁to ▁the ▁north . ▁Progress ing ▁east ward , ▁the ▁highway ▁continues ▁through ▁mostly ▁resident ial ▁areas ▁in ▁Sc ar borough , ▁eventually ▁reaching ▁the ▁Rou ge ▁Valley ▁on ▁the ▁city ' s ▁eastern ▁edge ▁and ▁crossing ▁into ▁Pick ering . ▁ ▁West ▁of ▁Pick ering , ▁Highway   4 0 1 ▁again ▁meets ▁former ▁Highway   2 , ▁which ▁there after ▁par alle ls ▁it ▁to ▁the ▁Ontario – Que bec ▁border . ▁As ▁the ▁highway ▁approaches ▁Bro ck ▁Road ▁in ▁Pick ering , ▁the ▁collect or ▁and ▁express ▁lan es ▁conver ge , ▁narrow ing ▁the ▁ 1 4 - lane ▁cross - section ▁to ▁ 1 0 , ▁divided ▁only ▁at ▁the ▁centre . ▁It ▁remains ▁this ▁width ▁as ▁it ▁passes ▁into ▁Ajax , ▁before ▁narrow ing ▁to ▁six ▁lan es ▁at ▁S alem ▁Road . ▁Pl anned ▁exp ans ions ▁east ▁of ▁S alem ▁to ▁improve ▁flow ▁leading ▁into ▁the ▁Highway   4 1 2 ▁and ▁L aker idge ▁Road ▁inter changes ▁will ▁see ▁the ▁highway ▁w iden ed ▁to ▁ten ▁lan es ▁as ▁far ▁as ▁Bro ck ▁Street ▁in ▁Whit by , ▁where ▁the ▁existing ▁inter change ▁will ▁be ▁re config ured . ▁ ▁East ▁of ▁Ajax , ▁the ▁highway ▁passes ▁through ▁the ▁second ▁ 3 . 5   km ▁(