The crossing is initiated by approaching trains and has no direct signaller involvement when working normally, apart from monitoring the process. The obstacle detection uses LIDAR and RADAR systems to detect that the crossing is clear, if it is not the sequence is disrupted and any approaching train would come to a stand at the protecting signal. The signaller would then be required to initiate an alternative operating procedure. This type of crossing has become much more common on many lines through the country and these crossings are now considered the safest of the modern types. The first crossing of this type was developed and tested in 2010, at a level crossing at Filey, North Yorkshire. These crossings are exactly the same as MCB-CCTV crossings except the barriers stay down and the lights stay off. When a user wants to cross, they have to press a button to notify the signaller, who will raise the barriers if there is no train. There are only a handful of these in the UK, one being at Barnetby, Lincolnshire. Automatic Half Barrier crossings are initiated by approaching trains and are not interlocked with signals, although they are monitored by a signaller for correct operation. The maximum rail line speed over these crossings is and only a maximum of two tracks can be crossed. The crossings have two half-barriers that only close the entrance lanes to the crossing, standard crossing road-lights and audible alarms. At the maximum rail line speed, the crossing warning time is typically about 27sec from the Amber light first showing to the train arriving at the crossing. These crossing were originally designed for use on roads with infrequent traffic. No new crossings of this type are likely to be installed and many AHBs are being renewed as MCB-OD or MCB-CCTV. In recent years, some audible alarms at AHBs have been updated to include spoken warnings as a means to improve safety. The first crossing of this type in the UK was installed in the town of Spath, near Uttoxeter in Staffordshire, and began operating on 5 February 1961. An open crossing, with conventional road-lights and audible alarms, but no barriers. On twin tracks an 'Another Train Coming' light is provided which flashes a red light with an 'another train coming' message when appropriate. Designed for low traffic railway lines and low traffic roads, the maximum line speed over these crossings is . On the railway approach, a Drivers Crossing Indicator(DCI) shows a flashing red light when the crossing is open to road traffic.