If you want to see how things are playing out with the expansion of dual credit courses, have a look at this article in the Houston Chronicle by Ericka Mellon. Due to recent legislation, most obstacles to dual credit course offerings have been lifted.
Furthermore, a 2015 law allows Harris County school districts to partner with any community college, not solely the one in their designated boundary, to offer the increasingly popular courses, according to the article.
Here is some background from the piece:
Leaders of Harris County's largest community colleges joined with local school district officials Wednesday to tout an average 14 percent gain in dual-credit participation since last spring. Preliminary estimates from Lone Star College, Houston Community College, San Jacinto College and Lee College show that their combined enrollment hit roughly 22,260 students this semester.
Over the last decade, the dual-credit movement has exploded across Texas and the nation - growing an average of 7 percent a year in the United States - as educators and policymakers strive to better prepare students for college and the workforce. Data from local community colleges shows that high school students who take the courses are more likely to earn a degree.
The push to increase dual-credit offerings in Houston's competitive community college market had spawned a turf war in recent years. Terry Grier, former superintendent of the Houston Independent School District, publicly criticized some of Houston Community College's programs in 2013 and began pushing for legislation to allow HISD to team with other colleges without needing HCC's approval.
The article mentions concerns by some critics that dual credit courses lack sufficient rigor. This is difficult to quantify, of course, but so far students in these programs tend to succeed later in their academic career. Now that dual credit is mainstream, we will have to see if these positive numbers continue.