I think I know the answer. In the Crash Time 1 mission "Murder at km 109", there is a piece of dialogue from an answering machine printing out a date of "Friday, March 30". Crash Time 1 came out in 2007 and March 30, 2007, was on a Friday. Using this information, it can be speculated that the seven cases take place in the week of March 29 to April 5, 2007. Also, it can be assumed that all the games are set in the year they are released (Nitro is in 2006). Plus, some events line up with the TV series. Tom Kranich has died events of Nitro, Chris Ritter has died after the events of Crash Time 1. Now, for Burning Wheels. Chris Ritter was known to own the Ben B32, as it has a license plate of "CR 10". This even makes more sense with the TV series, as Chris Ritter drove the Mercedes-Benz C 350 before Ben took ownership of the car after his death. Now, when did Chris Ritter die? Well, his death episode aired in April 2008. So it's possible that Burning Wheels is set during the summer of 2008. Highway Nights is definitely in the late summer (possibly August) of 2009 since it doesn't appear very light in the game. As for The Syndicate, it is summer 2010. And Undercover? Well, I'd say it's around the fall of 2012 since the trees are yellowing on the autobahn map and there is some snow in the Alps, but not much to make the roads slippery.