This　work　investigates　a　new　dynamic　bus　lane　reservation　problem　considering　dynamic　traffic　demand.　It　is　to　optimally　decide　which　road　links　in　the　bus　transit　network　to　set　up　reserved　bus　lanes　and　determine　when　they　are　implemented.　The　objective　of　the　problem　is　to　minimize　the　total　cost　of　the　transportation　network,　including　construction　costs　and　travel　time　costs　for　travelers.　We　formulate　the　problem　as　a　new　bi-level　programming　model.　The　upper　level　is　to　optimize　where　and　when　bus　lanes　are　implemented,　while　the　lower　level　contains　the　modal　split,　traffic　assignment,　and　transit　assignment.　An　improved　genetic　algorithm　is　proposed　for　solving　the　proposed　model　and　converges　to　a　satifactory　solution.　Computational　results　of　a　case　study　verify　the　effectiveness　and　efficiency　of　the　proposed　method.　©　2022　IEEE.