The crossings did not have road markings until the mid 50s, just shiny metal squares in the tarmac. Belisha beacons were also not illuminated originally - just orange enamelled metal globes. Flashing beacons and rerd / black stripes were introduced to help motorists see the crossings in darkness, and although the origin of the name "Zebra Crossing" is disputed, it is generally attributed to British M.P. James Callaghan who, in 1948, visited the country's Transport Research Laboratory which was working on a new idea for safe pedestrian crossings. On being shown a black and white design, Callaghan is said to have remarked that it resembled a zebra.