Let me define digital transformation in transportation with an example.

Years back, I use to keep on waiting for my bus. Now, I can track my bus and schedule accordingly. I am getting information about the traffic and delay time, which I can use it productively as well I can calculate my travel time to bus stop.

That's the digital transformation in Transportation. Digital transformation has given me power to track and monitor my transport.

Cheers!

Driving behavior quantification, information analytics and safety technologies (including big data, AI and eventually autonomous cars) can be counted as part of digital transformation in transport. 

I simply define Digitalisation in Transportation as the availability of transport information in a digital form. It is the elimination of intransparency by transport entities (infrastructure, vehicles, travelers, goods) which provide and digest information. That means an awareness of entity position, state, condition, and association with other entities and the ability to communicate this. If the entities can draw conclusions from that we have an Intelligent Transportation System. 

May be that this definition should also refer to:

Physical Internet + SaaS (Software as a Service) 

Thank you all for your answers. It's very useful for me.

To my opinion the evolution of the so called "connected vehicle" (otherwise known as cooperative intelligent transport systems), from the previous dumb, non communicating vehicle to a vehicle that connects to other vehicles and the infrastructure *so called vx or vany communications, is the step that epitomises digital transformation in transportation

Digital transformation in transportation is a process of achieving smart mobility via intelligent system propelled by information and communication technology

as a part of circular economy such transformation brings smaller, greener, flexible autonomous vehicles that impact transportation in smart cities