Texas is adding more than 1,000 new residents every day, and they all bring cars, pickups and SUVs. The state’s population is projected to jump another 50 percent by 2035, a staggering 14 million more Texans, equal to the current combined populations of the Dallas-Fort Worth and Houston metro areas.

A significant part of that growth is occurring in the San Antonio region. San Antonio is the fastest-growing big city in the country. Our local population will increase by 1.1 million residents by 2040.

Every day in the San Antonio region, these new residents are helping drive new vehicle registrations to 120 per day. Unfortunately, they don’t bring any roads with them.

One of the most difficult challenges facing our growing state and region is maintaining and expanding a highway system in the face of massive population growth, while at the same time dealing with aging roadways and the rapidly expanding number of big trucks that fill our highways while keeping the Texas jobs machine spinning.

A decade ago, the Texas Transportation Commission assembled the 2030 Committee, a blue-ribbon group charged with providing an independent assessment of the state’s highway mobility needs through 2035. They concluded that the state needed more than $5 billion a year in additional funding just to maintain existing traffic conditions at that time.

When the comprehensive Texas Transportation Plan 2040 was prepared in 2014, it also concluded that about $5 billion a year in additional funding would be needed just to keep congestion and road safety from getting worse.

The Legislature went to work on the funding shortfall, and in 2014 and 2015, voters approved Proposition 1 and Proposition 7, two state constitutional amendments that, when in full effect next year, will dedicate about $3.5 billion a year in sales taxes and oil and gas production taxes to highway improvements. Both these revenue streams have the potential to grow in future years.

The Legislature also took a big step in 2015 by ending the practice of diverting about $600 million a year from the State Highway Fund to nontransportation purposes. Still, a total of $4.1 billion in transportation funding in 2020 has far less buying power than the $5 billion gap identified in 2009.

Together, decisions to redirect existing state revenues to highways has gone a long way toward dealing with our shortfall. Utilizing new funding, plus traditional fuel taxes and vehicle registration fees, the Texas Department of Transportation now anticipates it will be able to award $6 billion to $7 billion a year in highway contracts over the next 10 years. But that will only be true if lawmakers stay the course.

Even with our successes, there is much more to do if we are to meet Texas’ long-term transportation funding needs. For example, TxDOT’s San Antonio district alone has 33 critical projects that require an additional $12.9 billion in funding that is simply not available during the next 10 years. As for statewide needs, the list of necessary but unfunded projects in the 10-year planning horizon exceeds $60 billion.

When legislators set up Proposition 1 and Proposition 7, they included potential termination dates that will cut off those tools unless extended by lawmakers. Unless lawmakers act, Proposition 1 will expire in just five years. The same thing happens to sections of Proposition 7 related to the general sales tax in 2029 and vehicle sales tax in 2032. In their recent interim report, members of the Texas House Transportation Committee recommended to colleagues that all three statutory “sunset” dates be removed.

Highway mobility and safety in Texas will decline dramatically if the Legislature allows these critical transportation revenue sources to expire. The Legislature should vote this year to eliminate or, at a minimum, extend these expiration dates.

The voters of Texas did their job by approving Proposition 1 and Proposition 7 by votes of more than 80 percent. Preserving them should be an easy call for state lawmakers, but we need to remind our legislators that transportation funding and sustaining mobility remains a high priority. Let’s unlock gridlock in Texas.

Jim Reed is president of the San Antonio Medical Foundation and a past chairman of Transportation Advocates of Texas and the San Antonio Mobility Coalition.