I'm going to make you feel a bit more ill - contrary to the intro of the article, the PRC did not actually invent the mobile lethal injection van in 1997.
The first ever mobile lethal injection van was actually, as far I know, from Delaware in 1986 : http://www.doc.delaware.gov/deathrow/history.shtml [1]
Beyond lethal injection vans, around a half dozen countries also employed gas chamber vans, with the first known example being in Nazi Germany.
[1] For some reason Wikipedians came to a consensus that only Chinese execution vans should be mentioned in the article titled "Execution vans".