What is the simulation-to-reality gap and how is it addressed in AV development?

The sim-to-real gap refers to differences between simulation and real-world performance. Sources include: Sensor model inaccuracies (simplified noise, no lens effects); physics model limitations (tire-road interaction, aerodynamics); scenario simplification (traffic behavior, pedestrian motion); and rendering quality (lighting, materials). Addressing includes: High-fidelity sensor simulation (ray tracing, learned sensor models); physics engine validation against real data; scenario replay using recorded sensor data; domain randomization (varying simulation parameters to improve generalization); and progressive testing (simulation, track, public road). Bridging the gap is critical because unsafe behaviors in reality may not appear in simulation.