Civil servants are concerned that special road markings for optically-guided buses could cause confusion among road-users. The Department for Transport has raised the issue in talks with promoters of the technology, which is new to the UK. Internal documents disclosed under the Freedom of Information Act also noted that raised kerbs could prevent conventional buses deploying wheelchair ramps, if bus stops were shared. Optical-guidance systems use a camera reading thick, parallel white lines to steer buses so they dock closely at bus platforms. The lines could conflict with existing ‘give way’ markings at side roads, central lane chevrons and bus stop clearways, according to the DfT. Officials have visited Rouen, in France, to see the Siemens technology in action, and confirmed no new legislation would be required. Stagecoach, which has an agreement to exploit the Siemens technology in the UK, is planning a trial for Cambridge. Andy Campbell, managing director of Stagecoach Cambridgeshire, speculated that cycling groups in the city were behind the request. ‘We have agreed we wouldn’t put markings across junctions,’ he said. ‘I can’t see how broken white lines would interfer with yellow box markings [at bus stops].’ Docking platforms would not hinder manual ramps, and no other operator in Cambridge was using electronic ramps, he added. Subject to county council approval, the trial would go ahead in summer 2007 on the city’s park-and-ride service, which serves five sites with 22 vehicles, Campbell said. The approval mechanisms had largely been resolved, said Cambridgeshire network manager ~Richard Preston~ Road markings were ‘one of the issues a trial would assess’. Raised kerb upstands were increasingly common. The trial’s cost and funding had still to be agreed.