The DEA has a helicopter flying looking for the crash site. It can see the smoke from the fire set by the gun thugs, but not their getaway vehicle. In flat terrain such as that area of Texas, the helicopter would be able to see the vehicle for miles, so it could not have escaped as was shown.
The bad girl flees on a street bike and Parker Texas Ranger chases her on a dirt bike. The chase takes place on pavement. Dirt bikes are geared for off-road use and cannot go anywhere near as fast as a street bike. As such, combined with the head start she had, the bad girl would have left Parker Texas Ranger far behind.