Physics objects sliding along surfaces

I've got a very game-specific problem, I'm simulating a motorcycle as a capsule collider and sliding it along a long flat surface. The issue is that I need a loooong surface that extends itself as you go, an infinite road essentially. So I create a script that instantiates new road pieces as the player motorcycle continues forward, but this leaves "seams" at the intersection of these road pieces. The road pieces are placed at the exact same position, but the physics still has trouble with them at times and every once in a while the capsule, which is being propelled forward simply with rigidbody.AddForce() calls, will "buck" as if it hit a tiny jump or something.

I've tried using a plane and a box collider for the long flat surfaces, but I get the same results with both. In addition to the physical problems, I have weird lighting flashes when switching between sections, I assume because the lighting is being calculated per face and there are slight inaccuracies between the two pieces.

I've likened the problem to what you get in complex water slides composed of multiple pipe pieces, I always hated the feeling of going over a seam and it would hurt my back after a few goes.

I've considered just putting a band-aid over the problem and damping unexpected impulses, but that's pretty hack-ish and I'm only about a week into the project :P

Anyone else run into this and come up with a clever solution?