Ability to scale up from toy examples to real life problems is a crucial issue for formal methods. Formalizing a algorithm used in vehicle automation (platooning control) in a certification perspective, we had the opportunity to study the scaling up when going from a (toy) model in 1D to a (more realistic) model in 2D. The formalism, Event-B, belongs to the family of mathematical state based methods. Increase was quantitative: 3 times more events and 4 times more proofs; and qualitative: trigonometric functions and integrals are used. Edition and verification of the specification scale up well. The crucial part of the work was the adaptation of the mathematical and physical model through standard heuristics. The validation of temporal properties and behaviors do not scale up so well. Analysis of the difficulties suggests improvements in both tool support and formalism.