KELLER (CBSDFW.COM) – Just days before school starts, some parents in Keller are still concerned about how their children will get there.

Keller ISD started a pay-to-ride school bus plan this summer because of a budget shortfall.  The district needs at least 50 children on each bus for this program to pay for itself.

On Tuesday they sent out emails and made phone calls to homes, reminding parents that even if they were right down the road from a school, they can still buy a ride if they want one.

LaShonda McGrew was online Tuesday to find out where her son and daughter will catch the bus to Keller High School next week.

She is paying for the service – $320 this semester – but is starting to get worried about how long the ride will last.  “A lot of us are not seeing where you’re going to have enough children, the parents that are going to sign their children up to do this.”

McGrew’s children are two of just 2,300 who have paid to ride to school next week.

Last year, more than twice that number of regular education students (5,200) rode the bus.

If buses aren’t full on the 72 planned routes they could be combined, or eliminated.  “Just like in past years, transportation is constantly assessing those things, even on a daily basis, looking at the ridership totals. Changing bus routes is nothing new, it happens every year,” Says Keller ISD spokesman Bryce Nierman.

Some parents in the district started receiving a phone message Tuesday night telling them how to sign their child up.  A similar email reminding them to sign up and find their new bus stop also went out.

The district said it was just a reminder for people, since the decision to do this was made just three weeks ago.

They said routes will only be taken away if there’s no need for them, but some parents are already making back up plans.

“Some of the people are trying to come up with different car pools but you’ve only had less than month to come up with all of this and this is rearranging a lot for peoples lives,” says McGrew.

The district expects more families to sign up as the week goes on.  So far, just 80 riders have signed up at a reduced rate of $100 per semester.