Condensed version: I wish to divide all the streets of a city into 200-meter-long segments. I tried using v.split.length in the GRASS toolbox in QGIS 2.18.13, but it didn't work for me: instead of creating 200 m segments, it divided all streets at intersections.
Long version: I obtained a shapefile of centerlines of all streets in Oakland CA from the city's database. There were multiple entries of the same street name occurring in the database, one entry for each segment of street between two intersections. For e.g., if Adeline Street goes through 3rd to 35th Streets, there would be 32 instances of "Adeline" in the database. I first processed this shapefile using the "Dissolve" feature in QGIS to merge all same-streets into one (i.e., to create one long "Adeline" street entry). However, when I attempt to run v.split.length to divide these dissolved streets into 200 m segment (to go with previous example) instead of splitting Adeline into 200 m segments, it breaks it into 32 segments, occurring between Adeline+3rd and Adeline+35th.