diff --git a/src/graph_utilities.jl b/src/graph_utilities.jl
index 4ea605a..38c14cd 100644
--- a/src/graph_utilities.jl
+++ b/src/graph_utilities.jl
@@ -4,8 +4,8 @@
 
 Maps node index to node id.
 """
-index_to_node_id(g::OSMGraph, x::DEFAULT_OSM_INDEX_TYPE) = g.index_to_node[x]
-index_to_node_id(g::OSMGraph, x::Vector{<:DEFAULT_OSM_INDEX_TYPE}) = [index_to_node_id(g, i) for i in x]
+index_to_node_id(g::OSMGraph{U}, x::U) where U = g.index_to_node[x]
+index_to_node_id(g::OSMGraph{U}, x::Vector{<:U}) where U = [index_to_node_id(g, i) for i in x]
 
 """
     index_to_node(g::OSMGraph, x::DEFAULT_OSM_INDEX_TYPE)
@@ -13,8 +13,8 @@ index_to_node_id(g::OSMGraph, x::Vector{<:DEFAULT_OSM_INDEX_TYPE}) = [index_to_n
 
 Maps node index to node object.
 """
-index_to_node(g::OSMGraph, x::DEFAULT_OSM_INDEX_TYPE) = g.nodes[g.index_to_node[x]]
-index_to_node(g::OSMGraph, x::Vector{<:DEFAULT_OSM_INDEX_TYPE}) = [index_to_node(g, i) for i in x]
+index_to_node(g::OSMGraph{U}, x::U) where U = g.nodes[g.index_to_node[x]]
+index_to_node(g::OSMGraph{U}, x::Vector{<:U}) where U = [index_to_node(g, i) for i in x]
 
 """
     node_id_to_index(g::OSMGraph, x::DEFAULT_OSM_ID_TYPE)
@@ -22,8 +22,8 @@ index_to_node(g::OSMGraph, x::Vector{<:DEFAULT_OSM_INDEX_TYPE}) = [index_to_node
 
 Maps node id to index.
 """
-node_id_to_index(g::OSMGraph, x::DEFAULT_OSM_ID_TYPE) = g.node_to_index[x]
-node_id_to_index(g::OSMGraph, x::Vector{<:DEFAULT_OSM_ID_TYPE}) = [node_id_to_index(g, i) for i in x]
+node_id_to_index(g::OSMGraph{U,T}, x::T) where {U,T} = g.node_to_index[x]
+node_id_to_index(g::OSMGraph{U,T}, x::Vector{<:T}) where {U,T} = [node_id_to_index(g, i) for i in x]
 """
     node_to_index(g::OSMGraph, x::Node)
     node_to_index(g::OSMGraph, x::Vector{Node})
@@ -38,30 +38,30 @@ node_to_index(g::OSMGraph, x::Vector{Node}) = [node_id_to_index(g, i.id) for i i
 
 Maps node index to dijkstra state (parents).
 """
-index_to_dijkstra_state(g::OSMGraph, x::DEFAULT_OSM_INDEX_TYPE) = g.dijkstra_states[x]
+index_to_dijkstra_state(g::OSMGraph{U}, x::U) where U = g.dijkstra_states[x]
 """
     node_id_to_dijkstra_state(g::OSMGraph, x::DEFAULT_OSM_ID_TYPE)
 
 Maps node id to dijkstra state (parents).
 """
-node_id_to_dijkstra_state(g::OSMGraph, x::DEFAULT_OSM_ID_TYPE) = g.dijkstra_states[node_id_to_index(g, x)]
+node_id_to_dijkstra_state(g::OSMGraph{U,T}, x::T) where {U,T} = g.dijkstra_states[node_id_to_index(g, x)]
 """
     set_dijkstra_state_with_index!(g::OSMGraph, index::DEFAULT_OSM_INDEX_TYPE, state)
 
 Set dijkstra state (parents) with node index.
 """
-set_dijkstra_state_with_index!(g::OSMGraph, index::DEFAULT_OSM_INDEX_TYPE, state) = push!(g.dijkstra_states, index, state)
+set_dijkstra_state_with_index!(g::OSMGraph{U}, index::U, state) where U = push!(g.dijkstra_states, index, state)
 """
     set_dijkstra_state_with_node_id!(g::OSMGraph, index::DEFAULT_OSM_ID_TYPE, state)
 
 Set dijkstra state (parents) with node id.
 """
-set_dijkstra_state_with_node_id!(g::OSMGraph, node_id::DEFAULT_OSM_ID_TYPE, state) = push!(g.dijkstra_states, node_id_to_index(g, node_id), state)
+set_dijkstra_state_with_node_id!(g::OSMGraph{U,T}, node_id::T, state) where {U,T} = push!(g.dijkstra_states, node_id_to_index(g, node_id), state)
 """
     maxspeed_from_index(g, x::DEFAULT_OSM_INDEX_TYPE)
     maxspeed_from_node_id(g, x::DEFAULT_OSM_ID_TYPE)
 
 Get maxspeed from index id or node id.
 """
-maxspeed_from_index(g, x::DEFAULT_OSM_INDEX_TYPE) = index_to_node(g, x).tags["maxspeed"]
-maxspeed_from_node_id(g, x::DEFAULT_OSM_ID_TYPE) = g.nodes[x].tags["maxspeed"]
\ No newline at end of file
+maxspeed_from_index(g::OSMGraph{U}, x::U) where U = index_to_node(g, x).tags["maxspeed"]
+maxspeed_from_node_id(g::OSMGraph{U,T}, x::T) where {U,T} = g.nodes[x].tags["maxspeed"]
\ No newline at end of file