Directors might be buying to make it look like they are positive...

Directors might be buying to make it look like they are positive on the stock.
The company effectively issued a profit warning yesterday. Single digit million profits are looking pretty certain for FY18. And in the last few weeks google has started a full driverless taxi service in Phoenix and Uber has just ordered 24,000 driverless cars from Volvo. Even if you assume Australia is 2 years behind the US, that gives CAB about 4 years left.
If you are generous and assume $10m profit for the next 5 years that gives you $50m total future profits for the company compared to market cap of nearly $200m.
Uber with drivers takes CAB to $1.
Uber without drivers takes CAB to $0.