It doesn't matter. If the back of the tomb is facing a road, that is, parallel to the road, that is a very good thing. As the saying goes, "there is a way behind the monument" means "there is a way for the younger generation", which is very good.
Generally speaking, it doesn't matter. I work in a cemetery. There are roads around every cemetery here. For the convenience of sweeping the grave, so don't worry, you will be fine!