13-transport.Rmd: add a few more fixes

13-transport.Rmd

@@ -51,7 +51,7 @@ Routes (which can be represented as single linestrings or multiple short *segmen
 They can be represented as geographic features (typically short segments of road that add up to create a full network) or structured as an interconnected graph, with the level of traffic on different segments referred to as 'flow' by transport modelers [@hollander_transport_2016]
 
 Another key level is **agents**, mobile entities like you and me and vehicles that enable us to move such as bikes and buses.
-These can be represented computationally in software such as [MATSim](http://www.matsim.org/) and [A/B Street](https://github.com/a-b-street/abstreet), which represent the dynamics of transport systems using an agent-based modeling (ABM)\index{agent-based modeling} frameworks, usually at high levels of spatial and temporal resolution [@horni_multi-agent_2016]. 
+These can be represented computationally in software such as [MATSim](http://www.matsim.org/) and [A/B Street](https://github.com/a-b-street/abstreet), which represent the dynamics of transport systems using an agent-based modeling (ABM)\index{agent-based modeling} framework, usually at high levels of spatial and temporal resolution [@horni_multi-agent_2016]. 
 ABM is a powerful approach to transport research with great potential for integration with R's spatial classes [@thiele_r_2014; @lovelace_spatial_2016], but is outside the scope of this chapter.
 Beyond geographic levels and agents, the basic unit of analysis in many transport models is the **trip**, a single purpose journey from an origin 'A' to a destination 'B' [@hollander_transport_2016].
 Trips join-up the different levels of transport systems and can be represented simplistically as geographic *desire lines* connecting *zone* centroids\index{centroid} (*nodes*) or as routes that follow the transport *route network*.
@@ -93,7 +93,7 @@ tm_shape(region_all[1, ], bbox = region_all) +
   tm_basemap(server = leaflet::providers$Esri.WorldTopoMap)
 ```
 
-```{r bristol, echo=FALSE, fig.cap="Bristol's transport network represented by colored lines for active (green), public (railways, black) and private motor (red) modes of travel. Black border lines represent the inner city boundary (highlighted in yellow) and the larger Travel To Work Area (TTWA).", fig.scap="Bristol's transport network."}
+```{r bristol, echo=FALSE, fig.cap="Bristol's transport network represented by colored lines for active (green), public (railways, blue) and private motor (red) modes of travel. Black border lines represent the inner city boundary (highlighted in yellow) and the larger Travel To Work Area (TTWA).", fig.scap="Bristol's transport network."}
 knitr::include_graphics("figures/13_bristol.png")
 ```