i have also attempted to get this working, the way I figured out getting speed is by manually taking a screenshot of each number and saving those images then finding the best match to the speed shown while running. note that its a bit tricky since it is not 100% opaque
A neural network, given the last 3 frames, can determine speed and acceleration by itself, probably better than reading the console, since the car can drive backwards and still have high speed, and the car can also be falling, turning, etc. and the nn can figure that out. Wpould take a bit longer to train though.