```r
ways_freeway = bristol_ways %>% filter(maxspeed == "70 mph") 
ways_sln = SpatialLinesNetwork(ways_freeway)
slotNames(ways_sln)
#> [1] "sl"          "g"           "nb"          "weightfield"
weightfield(ways_sln)
#> [1] "length"
class(ways_sln@g)
#> [1] "igraph"
```