A £15,000 piece of hi-tech kit bought to banish congestion in Portsmouth has now been fitted.
The city council spent the money on technology enabling signals on roads around the city centre to be synchronised.
It means traffic lights on Church Street roundabout, Commercial Road North and Marketway can all be changed to green during busy periods to keep drivers moving.
It comes as the council has decided to amend the layout of the M275 route into the city by shortening the bus lane on Mile End Road.
Leader Cllr Donna Jones said the changes to the controversial road layout have come about because she saw for herself each day how jams had worsened.
Crossings in Commercial Road North and Marketway are also being upgraded with sensors to detect when pedestrians have reached the pavement to allow traffic to immediately carry on.