Kenmare Economic Conference:  Policy must recognise that buses provide the optimal form of public transport for Dublin and "not light rail, heavy rail or Metro", Dublin's director of traffic has said. From Cliff Taylor in Kenmare

"The difficulties in constructing Luas and the announcement of weekend DART disruption highlight the difficulties of fixed-rail systems," said Mr Owen Keegan, who was addressing the annual Kenmare Economics Conference in Co Kerry.

"Too often, bus is seen as a short-term, stop-gap measure until we get a real public transport system. The view that bus is an inferior form of public transport that permeates official thinking needs to be quashed," Mr Keegan said.

The new QBCs being developed for the Rock Road/Merrion Road on Dublin's southside and the Howth Road on the northside will compete directly with the DART and he was confident they would "demonstrate the superiority of bus in Dublin".

Already the introduction of QBCs had attracted more people to use buses and had contributed to a falling share of car journeys in total trips.

"While the outlook for bus has never been better, it is disappointing to note that the service enhancements such as integrated ticketing and the roll-out of real-time passenger information which were promised in the original DIT strategy in 1994 have not been delivered and are still some years off," he told the conference.

Meanwhile, allowing private firms to compete in the bus market could further stimulate innovation and improve services, while peak fare structures in public transport - charging more to travel at peak times - could ease congestion during the rush hour.

Looking at other transport issues, Mr Keegan said "the problem of car trips to school needs to be tackled, possibly through providing schools with financial incentives to change opening hours. Meanwhile, the provision of improved pedestrian and cycling facilities needs to be taken seriously."

The media focus on major projects, meanwhile, meant there was a risk of losing the focus on lower cost solutions to traffic issues, he said. The "edifice complex" of concentrating on major projects would lead to difficulties "when it becomes obvious to the general public that the promised land of congestion reduced to 1991 levels and a rail-based public transport system easily accessible to all is simply not on the horizon".

The opening session of the annual economists' conference on transport and the environment was also addressed by Prof Frank Convery of UCD's Department of Environmental Studies.

He made a strong defence of plans to introduce a carbon tax to cut greenhouse gas emissions, saying this signal was vital if we were to meet our targets of reducing emissions, contained in the Kyoto Protocol.

Combining the tax - which is due to be introduced by the end of next year - with other measures such as better regulation, information and negotiated agreements could lead to a significant fall in emissions, he said.

"The reaction to the price signal will tell us more in three months than 30 years of ex ante modelling," he told the conference.

There is a presumption that most of the easily achieved abatement of emissions will be from the electricity sector, "but this may not indeed be the case".

Negotiated agreements, under which companies could trade emission licences, provided a mechanism for meeting both environmental and economic goals, he said.

Prof Convery also called for a "singular focus" on looking at how emissions could be cut in the transport sector and continued public support for wind power, to help increase its market share.