The crowded roads in Houston are not going to get any roomier any time soon.

The initial demographic analysis performed by the Houston-Galveston area council as it considers future transportation projects indicated that the population in the eight county Houston region is likely to increase by 3.3 million by 2040. The analysis also found the number of registered vehicles in the state is likely to double within that time frame.

The growth Houston is facing has made mobility planning a critical priority, said Roland Strobel, chief transportation planner with H-GAC. The council recently began the 18-month process of updating the Regional Transportation Plan—a long-term evaluation of transportation issues facing the city with proposals for the best ways to deal with them. The plan, which currently focuses through 2035, will be updated to extend its grasp to 2040.

"This is essentially a blueprint for what our transportation system will look like in 30 years," Strobel said. "We get a sense of how fast our region is growing, new data on demographics and finances, and we go back and update the plan about every four years."

Over the next 18 months, H-GAC will gather public input and evaluate various transportation scenarios and funding possibilities. After the RTP is adopted in summer 2014, the project selection process screens which transportation projects are built and when.

The big budget items on the current RTP include the Grand Parkway and various improvements to Hwy. 290, I-45 and Beltway 8. Hwy. 249, which is being paid for by the Harris and Montgomery County toll road authorities, is listed as a priority project, but does not require the state or federal aid that the other projects do.

Despite the stark increase in people and vehicles in the state, Strobel pointed out that Texas is also urbanizing, making driving less of a necessity for more people. While the number of registered vehicles is increasing by 100 percent, the number of miles traveled in Texas is only projected to increase by 55 percent.

"We don't have to drive as far to get to the places we need to be," he said.

To find out more about the 2040 RTP, submit feedback on what its priorities should be and to participate in H-GAC's transportation survey, visit www.2040rtp.org.

"We want to do this on a cooperative level where we get everyone involved," Strobel said. "We want to make sure all voices are heard and each region gets its fair share."