When I worked at Arriva, I'm pretty sure the deckers there had no bridge warning system. GNE deckers do. Where the system falls down is something like a coach (an air conditioned Levante is 12'9) however there is no bridge warning system but there are some bridges you can get a single decked bus under but the coach would hit the bridge. What there should be is a system similar to that in some cars (Levantes have it, amongst other safety features) where if a sensor detects an obsticle, the brakes are applied.

As for other bits of kit fitted, GNE have RIBAS which monitors drivers driving skills and gives them a weekly score (most drivers don't care about this) but according to managers (when it was rolled out...again) "the insurance company requires it to be fitted as a condition of the policy."

Arriva have (or had) Econospeed fitted. I believe they have (or had) shares in the company that developed it.

What about costs of maintenance for radio systems. Arriva don't (or didnt) have radios and you could claim expenses for phone calls when you inevitably broke down. GNE has two radio systems- Tait and Motorola. You can also send and receive messages on the ticket machines when the radio doesn't work or isn't fitted to a vehicle (very frequently).