Python is as software goes, a fairly easy programming language to learn and judging by the size of the open-source community supporting it, it is extremely popular. It's popularity with autonomous vehicle engineers is largely due to the various available resource libraries such as AI, deep learning and data visualization. The disadvantage is with its large size which makes it data intensive for high performance applications.

Further reading
Linux - OS for Autonomous vehicle computing
Linux Foundation - Training and Certification courses
C++programming language for autonomous vehicle computer programming
Autotalks - Autonomous vehicle production software platform
Tensyr - Autonomous vehicle production software platform
Ceva Deep learning Software Framework wins award
AutoNOMOS (Autonomous Vehicle Software)
Tesla Autopilot software to use advanced radar technology