I took the twenty six teams that finished ranked in either poll in 2008, and looked at how long it had been since they beat a team on the road that finished in the top 25 (in either poll).

Not one team had won its last two road games against teams that finished ranked. Nine of the 26 had won their last game, eight of them in 2008. #2/#4 Utah had the longest chronological drought, losing six games since beating CSU (10-2) in 1994. But several teams had a longer active losing streak:

#8/#8 Penn State had lost seventeen in a row since beating Illinois (8-4) in 1999.
#19/#16 Missouri had lost fourteen in a row since beating Oklahoma State (8-4) in 1997.
#24/#24 Michigan State had lost eleven in a row since beating Minnesota (10-3) in 2003.

#17/#17 Cincinnati had beaten the last ranked team they played (23/NR West Virginia), but had lost their previous thirty road games against EOS-ranked teams.

Half the teams had their last EOS-ranked road win against a team with four losses. The only ranked teams in '08 who had beaten a team with two or less final losses were Utah, Texas (beat 10-2 Ohio State in 2005), Georgia (beat 11-2 Auburn in 2006), Ole Miss (beat 13-1 Florida in 2008), and BYU (beat 11-2 TCU in 2006).

The mean for ranked teams that year was to have won one of their last 6.5 road games against EOS-ranked opponents. It's tough to beat good teams on the road. I expect the teams that were not ranked at EOS collectively had more dismal statistics.