Bus Driver Tacho Card?

[agent006]

I've been taking the bus to work lately, and being a huge nerd I sit up at the front sometimes and watch the driver.

I notice about half these times, the dash display is bright orange with a "Driving without a valid driver card" message and the card tray on the tacho is open.

Is there a requirement for Bus drivers to use a tacho card like HGV drivers?