Officials have calculated the economic damage caused by congestion in the East Midlands as almost £1bn a year.
The congestion report by the East Midlands Development Agency (Emda) estimates the cost to be £935m.
Six East Midlands councils will be examining it as they consider whether or not to introduce congestion charges.
The figure was reached by adding up time spent sitting in stationary traffic and other aspects including vehicle running costs.
Researchers also considered companies refusing to invest in the region because of their perceptions of the traffic problems.
Identified congestion trouble spots include the A52 between Nottingham and Derby, the A38 roundabouts near Derby and the A50 near its M1 junction.
Traffic congestion near Derby is said to cost £45m a year but that figure is about £150m each for Leicester and Nottingham.
The local authorities examining the figures are Nottingham City Council, Nottinghamshire County Council, Derby City Council, Derbyshire County Council, Leicester City Council and Leicestershire County Council.