Nationally, the Census Bureau reported 8.1 percent of commuters travel an hour or more each way to work. Harris County fared slightly better, with 7.6 percent of commutes taking an hour or more. Workers in neighboring counties had longer commutes; in Montgomery County, 14 percent of commutes took an hour or more.

The increase in commuting across county lines has led in recent years to greater use of toll lanes.

via Houston area among tops in U.S. for inter-county commuting – Houston Chronicle.