Dartford tolls suspended - in rush hours
The six-month experiment will result in the suspension of tolls at times of severe congestion.
Not all good news
Car drivers also face toll increases of up to 66% as the Government seeks to raise the £1.7 billion needed to fund extra crossing capacity.
It wants to raise the cost of crossing from the current £1.50 to £2 by the end of 2011 and to £2.50 in 2012.
The Dart-Tag fee will rise from £1 to £1.33 in 2011 and £1.67 in 2012.
Other measures to improve the flow of traffic will include the use of automatic numberplate recognition for pre-paying users from 2013.
More than 50 million vehicles use the crossing each year – an average of 137,000 per day. It was designed with a capacity of 135,000 vehicles per day.