are: 25, 29, 140, 149, 243, 207, 86, 36, 38, 5, 279, 53, 109, 141 and 43. Route U9 has the highest mean observed speed of daytime routes, at 18.8 mph. The slowest was 15H at 3.8 mph. Route X26, running from Croydon to Heathrow Airport, is the longest daytime route at 24 miles. The next longest are routes 166, 358 and 465 (all 17 miles), 111 and 246 (16 miles) and 492 (15 miles). References Bibliography Marshall, Prince Wheels of London; The story of London's street transport. The Sunday Times Magazine, 1972. . External links