This guy's conclusion generally supports the idea that reaction time is about 1.5 seconds.
First, your link is wrong:
"Sorry, the page or file you are looking for was not found (error 404)"
Second, check the methodology. None of the situations they created actually required the fastest reaction time of which the driver was capable.
Third, the ones that came closest to requiring fast reaction recorded 85th percentile (not median, mind) of far better than 2.5 seconds.
C.R.B. "Roadworks Ahead" Sign 3.0s (Doesn't require fastest reaction)
Protruding vehicle with tyre change 1.5s Lit vehicle under repair at night 1.5s
Parked Police Vehicle 2.8s (Doesn't require fastest reaction)
Amphometer: Beaconsfield 3.4s (Doesn't require fastest reaction)
Amphometer: Dandenong North 3.6s (Doesn't require fastest reaction)
Amphometer: Gisborne 3.6s (Doesn't require fastest reaction)
Amphometer: Tynong 2.54s (Doesn't require fastest reaction)
Railway crossing: Night (General Population) 1.50s
Railway crossing: Night (Rally drivers) 1.50s
Railway crossing: Day 2.53s (Doesn't require fastest reaction)
Car following 1.26s (Didn't follow their methodology).
-- Alan Baker Vancouver, British Columbia "If you raise the ceiling 4 feet, move the fireplace from that wall to that wall, you'll still only get the full stereophonic effect if you sit in the bottom of that cupboard."
