What is a period of availability under the Road Transport (Working Time) Regulations 2005?

In general, for the purposes of the Road Transport (Working Time) Regulations 2005 (SI 2005/639) a period of availability is waiting time during which the mobile worker is not required to remain at his or her workstation, but must be available to answer any calls to start or resume driving or to carry out other work. The mobile worker will know about the duration of the period in advance. Periods of availability can include periods when a mobile worker is accompanying a vehicle being transported by train or ferry, periods spent waiting at borders and periods of waiting due to traffic prohibitions. Periods of availability can also include time spent travelling in, but not driving, a moving vehicle as part of a team.