diff --git a/s1/index.qmd b/s1/index.qmd
index 906c3806..c90c1c54 100644
--- a/s1/index.qmd
+++ b/s1/index.qmd
@@ -8,6 +8,7 @@ execute:
   message: false
 ---
 
+
 ## Agenda {.unnumbered}
 
 1.  Lecture: an introduction to Transport Data Science (30 min)
@@ -171,6 +172,7 @@ casualty_type = c("pedestrian", "cyclist", "cat")
 casualty_age = seq(from = 20, to = 60, by = 20)
 crashes = data.frame(casualty_type, casualty_age)
 nrow(crashes)
+
 ```
 
 There are different ways to execute code.
@@ -282,6 +284,7 @@ Let's go through these exercises together:
 3.  **Bonus:** What is the difference between the output of `summary()` on `character` and `factor` variables?
 
 -   We'll explore this together
+## National Travel Survey 
 
 # Self-study practical (1 hr)
 
@@ -312,4 +315,4 @@ For details on installing packages see [here](https://docs.ropensci.org/stats19/
 
 -   Think of a research question that you could answer with data science, and write it down in a .qmd file. Include a sketch of the data you would need to answer the question.
 
--   Sign-up to the Cadence platform as outlined at [itsleeds.github.io/tds/s2/#the-cadence-platform](https://itsleeds.github.io/tds/s2/#the-cadence-platform)
\ No newline at end of file
+-   Sign-up to the Cadence platform as outlined at [itsleeds.github.io/tds/s2/#the-cadence-platform](https://itsleeds.github.io/tds/s2/#the-cadence-platform)