Houston’s light rail system opened nearly a decade ago, and its sole line has since become the 13th most traveled light rail route in the U.S. But the country’s top transportation czar still had some harsh words for the system, known as METRORail, during a press conference last week.

Lamenting that the Metropolitan Transit Authority of Harris County (METRO) has fallen short in extending light rail to the suburbs, U.S. Transportation Secretary Ray LaHood called on the region to “get its act together” to bring light rail to where the majority of Houstonians live, the Houston Chronicle reports.

Now averaging nearly 38,000 riders per day (in a city of more than 2.1 million), METRORail’s Main Street Line has moved a growing number of people across its 7.5 miles since opening in early 2004. Three additional lines, now under construction and expected to open next year, will grow the system to a total of 22 miles, according to the Chronicle.

But money problems and political opposition have stymied further development of light rail in the nation’s fourth-largest city. Initial plans for METRORail included no fewer than six different routes. Citing uncertainties in funding, Houston Mayor Annise Parker put the construction of two lines on hold in 2010.

Setbacks like this have given fuel to opponents of the expansion. U.S. Rep. John Culberson, who represents a Texas district that includes several upscale areas of Houston, told the Chronicle, “I look forward to the day when Metro publicly admits what they have privately told me: They can’t afford to expand light rail in the city.”

Meanwhile, regional voters that supported a 2003 referendum approving the new lines are waiting for their promised light rail to appear.

“The fact that these people voted for a referendum and are paying these taxes and have never seen any benefit from it is just not right,” said LaHood, who is stepping down as transportation secretary this year. Another referendum last year allowed MERTO to dedicate more sales tax revenues for transit, though much of that will go toward buses, which lost riders during the years when METRORail gained them.

Despite having a relatively cheap fare — a one-way ride costs $1.25 — and reaching the 100 millionth-rider milestone this spring, METRORail has struggled with people stealing free rides. Fares are collected on board instead of at turnstiles, giving riders many chances to shirk on paying. Last month officials announced plans to step up enforcement.

METRO expects the North, East and Southeast light rail lines to open next year. In late 2011, the Federal Transit Administration awarded the agency a $900 million grant to help complete construction on the North and Southeast lines.