The　aim　of　the　study　is　to　devise　a　new　reliable　dynamic　route　guidance　approach　by　integrating　the　A*　algorithm,　the　concept　of　reliability　and　an　existing　route　guidance　method　into　a　single　package.　A　new　purpose-developed　software　tool,　the　Imperial　College　Navigation　Software　(ICNavS),　is　presented,　so　as　to　implement　and　demonstrate　the　new　approach　on　a　real　road　network,　using　simulated　data.　A　summary　of　the　background　of　the　program　is　given,　followed　by　a　procedure　developed　in　order　to　model　the　features　of　real　road　networks　as　well　as　missing　data.　Then,　a　simulation　experiment　on　a　part　of　West　London＇s　road　network　is　carried　out　and　the　results　are　presented.