Lou Gehrig hit many more doubles on the road. Why?

Lou Gehrig hit doubles per at bat 48.5% better on the road than at home in Yankee Stadium.  Why?

	AB	R	H	2B	3B	HR	XBH	AB/XBH	XBH/H	AB/2B	AB/3B	AB/HR
home	3,861	882	1,269	206	83	251	540	7.15	42.55%	18.74	46.52	15.38
road	4,139	1,006	1,452	328	80	242	650	6.37	44.77%	12.62	51.74	17.10

Goudey card 1934
 via Wikimedia Commons

Click on this link to view detail data.  Obviously, I was gathering his home/road splits for home runs but couldn't help but notice the huge discrepancy in doubles.  I've been thinking about it but cannot come up with a reason.  His triple and home run rates are better at home and I guess that contributes but it would not seem to account for the entire difference.

Comments welcome.