First TRL study (for TfL) 2010
TRL first assessment study 2010
Assessment of TfL’s experimental scheme to allow motorcycles onto with-flow bus lanes on the TLRN 
The first study 10 months into the London trial was extremely detailed, with the primary objective of assessing changes on trial and control routes, but also on the wider TLRN bus lane network. Findings included:
• A migration of PTWs to main routes.
• Modal share appeared to remain relatively consistent.
• Bus and general traffic lane speeds were largely unaffected.
• PTW speeds had increased. On 30mph routes, the number of PTWs travelling at or exceeding the speed limit increased from 37% before the change to 46.7%.
• Motorcycle collision rates appeared to rise significantly. The increase in PTW collisions generally involved cars turning left into and out of side roads.
• The severity level of PTW collisions increased.
The study was conducted with great care taken to produce statistically robust data. However, it included just 10 months of collision data, the minimum required to accurately assess any reasonably large effects. TFL responded to this study with an enforcement and publicity campaign.