I was going to be rude, but I thought I’d just do you the courtesy and paste the relevant section from the article:

As it tends to be heavily trafficked, the overall bandwidth is a key consideration, and to that end one of the changes we made this week was to split the page content into a more basic page, augmented by a separate Javascript file with additional content beyond that. Since most of the traffic to the site is automated it tends not to fetch the Javascript file, reducing overall data requirements.

They’re using JS to reduce the load.

In the UK it’s common for country lanes to have a speed limit of 60 MPH, while only being metres (9 ft) wide. Including road widths is useful for some routing engines for both normal cars, and HGVs.