Instatiate inside OnTriggerEnter gives unwanted delay

Hello Everyone! I'm trying to create a scrolling street. Each time the street hits a box collider, more of the street (a new "street segment" if you will) is generated off screen so that it appears endless. My problem is that when I generate the next street segment there is a variable delay, creating openings between segments. This is especially apparent when I boost the speed at which the segments scroll. Here is my code currently; it is attached to an empty game object with a box collider called "StreetCollider":

 #pragma strict
 
 //Detects when a street hits the collider, creates and deletes streets
     
 var nextStreet : GameObject; //Pass it the next street to create
                              //Next step is to create randomstreet generator script and pass return
                              //value to this variable. Make this variable private.
     
 function OnTriggerEnter (currentStreet : Collider) {
     
     //Get some data from the current street
     
     //This helps to get the size of the currentStreet object's mesh
     var mf : MeshFilter = currentStreet.GetComponent(MeshFilter) as MeshFilter;
     var mesh = mf.sharedMesh;
     
     //Gets the mesh size and scale
     var size = mesh.bounds.size;
     var scale = currentStreet.transform.localScale;
     
     //Create a clone of what's passed to nextStreet
     if(Instantiate(nextStreet, Vector3(0, 0, -size.y*scale.y), currentStreet.transform.rotation))
         Debug.Log("Street collider collided with!");
         
 }
 
 function OnTriggerExit (currentStreet : Collider) {
     //Destroy the currentStreet when it exits the trigger
     Destroy(currentStreet.gameObject);
 }

I'm a programmer but I'm relatively new to the concepts of scripting versus more programmatic coding, so I'm a bit hazy on encapsulation methods and message passing in Javascript. Would calling a different function outside of OnTriggerEnter help? Would creating some of the data outside of OnTriggerEnter help and if so, where would I put the data? Could a possible fix include the FixedUpdate function?

Thank you for reading this and any help is greatly appreciated!