interstate maryland interstate runs tennessee landing new_york maryland interstate highway runs miles west_virginia state line north pennsylvania state line near primary north south interstate highway connecting north winchester south idea north south bypass relieve congestion contemporary main highway route interstate system construction began mid-1950s completed north pennsylvania state line assigned new freeway southern section freeway built starting completed interchange improvements changed little lane freeway 1960s long range plans widening lanes interchange improvements major corridor route description crosses west_virginia enters maryland lane freeway speed limit miles hour interstate curves northeast highway meets road diamond interchange exit south town virginia avenue ramp partial cloverleaf interchange exit east speed limit drops miles hour interstate passes edge suburb halfway highway meets memorial highway cloverleaf interchange exit collector distributor lanes traffic advised use west meets leads shopping centers including ramp partial cloverleaf interchange exit continues northeast west edge interstate crosses csx passes access reaching cloverleaf interchange national pike freeway intersects pike partial cloverleaf interchange exit immediately north partial interchange featuring loop exit ramp southbound straight entrance ramp northbound direction interstate curves north crosses speed limit increases miles hour interstate passes eastern edge highway meets avenue diamond interchange exit meets access regional airport cloverleaf interchange exit freeway gently curves airport runway interstate heads northeast pennsylvania state line highway meets road exit pennsylvania exit sequence southbound exit ramp entrance ramp maryland northbound ramps pennsylvania like interstate highways national_highway_system entire length shortest mainline interstate maryland contains shortest portion states interstate highway passes interstate dedicated history section constructed maryland pre interstate bypass planned provide relief existing north south highway downtown highway planned run west downtown pennsylvania state line continue bypass north tie near preliminary engineering bypass began construction began time southern extension planned south east freeway completed pennsylvania state line including interchange present alignment west downtown highway completed traffic followed road bypass extended pennsylvania tied modern exit new freeway marked beginning construction portion south began fill gap portion maryland portion interstate completed near southwest west_virginia bridge constructed relocated opened cloverleaf interchange future constructed including collector distributor lanes remainder highway south including bridge construction southern section west_virginia state line opened remains similar completed exit numbers marked exit numbers changed road interchange originally interchange reduced partial interchange interchange south originally northbound exit ramp southbound entrance ramp ramps direction added junction diamond interchange rebuilt partial cloverleaf interchange future heavily maryland 1960s era freeway commuter route rapidly growing metropolitan area major corridor highway minimum annual average daily traffic road maximum interstate long distance traffic alternative avoid traveling major cities east_coast result began developing long term plans upgrade entire length maryland state completed planning process eventual upgrades november step preliminary engineering work state plans expand lanes address capacity concerns addition interchanges rebuilt reduce eliminate weaving particular collector distributor lanes interchange extended north halfway boulevard interchange road interchanges changed cloverleaf interchange partial interchange removing loop ramps interchange converted partial cloverleaf interchange diamond interchange avenue diamond interchange loop ramp added westbound avenue southbound interchange acceleration lanes lengthened modern standards ramps interchange modified better handle traffic passing freeways auxiliary lanes added directions interchanges southbound avenue interchanges addition option construct truck weigh station state weigh stations maryland west_virginia segments exit list entire route
Interstate 81 in Maryland