Garrett and Ben will both play vital roles in delivering the Mayor's priorities in key areas.
TfL have announced two new senior appointments within its Surface Transport Division.
Garrett Emmerson has taken up the role of Chief Operating Officer of Streets and Traffic replacing Peter Brown who has recently retired.
Ben Plowden has taken up the new role of Director of Integrated Programme Delivery, which will bring together key projects including walking and cycling, road safety and smarter travel.
The Chief Operating Officer of Streets and Traffic is responsible for keeping London moving and helping to drive forward the Mayor's agenda to smooth traffic flow in the Capital.
The role oversees the operation, management and investment in the Transport for London Road Network (London's Red Routes), traffic signals, and traffic, incident and event management.
The Director of Integrated Programme Delivery is responsible for delivering integrated transport programmes across London to support sustainable travel.
This includes cycling and walking, road safety, bus priority, public realm improvements, smarter travel and freight.
Garret Emmerson was previously Director of Strategy and Policy in TfL Planning and joined TfL in 2008.
Ben Plowden was previously Director of TfL's Smarter Travel Unit and joined TfL in July 2002.
David Brown, Managing Director, Surface Transport, said: 'Garrett and Ben will both play vital roles in delivering the Mayor's priorities in key areas such as smoothing traffic flow and dramatically increasing the number of people cycling in the Capital.'