Considering they have a noticeably different set of players and have played half a season under a different manager, the Nationals' inability to win on the road is strikingly similar to last year. They won just 28 times away from Nationals Park in 2010, sidetracking a season that could have been respectable had they been able to approach what they did at home (41-40).
This year, they're almost certain to improve on the 69 wins they posted last year - they're currently at 68, with 17 games to go. But that's largely because they've been better at home.
With their win against the Mets on Monday night, the Nationals improved to just 27-44 on the road this season. That's the second-worst road record in the National League (only the 97-loss Astros are worse), and considering they have seven games left in Philadelphia and Florida - two places where they've struggled mightily over the years - the Nationals aren't likely to make a big jump in their final road record.
They've pitched worse on the road (they have a 4.11 ERA, 1.438 WHIP and 1.79 K/BB ratio on the road, compared to an impressive 3.42, 1.228 and 2.73 at home), and they've hit worse, too - their team OPS is just .664 on the road, and it's .731 at home. But beyond the numbers, there's no reasonable explanation for why the game should be any different. It might be because the team still has a number of young players - the best road teams in baseball are stocked with veterans - but there are younger teams like the Diamondbacks who have played reasonably well on the road, too.
Whatever it is, the Nationals need to figure it out before they're ever going to be a serious competitor. Only three playoffs teams have been worse than 10 games under .500 on the road since 2006, and only one headed to this year's playoffs (the Brewers) is likely to have a losing record away from home. Road success is one of the final hurdles good teams figure out how to climb, and until the Nationals figure it out, they can't legitimately expect to be any good.