THERE could be serious traffic jams around Dublin city over the next week as thousands of motorists who normally use the M50 could take alternative routes to avoid a controversial new barrier-free tolling system which came into effect at midnight.

No decision has yet been made on four proposed new tolls on the M50 motorway, Taoiseach Bertie Ahern told the Dáil tonight.

Transport Minister Martin Cullen turned the sod on an upgrade of the notorious M50 today signalling over two years of traffic disruption for motorists.