Maybe it's time to say "stop" to the way we've been developing our suburbs because it just hasn't worked out very well. That was the blunt message delivered by David O'Connor, the Fingal County Council architect, to a conference on housing last weekend, organised by the General Council of County Councils.

In an illustrated talk which challenged the whole basis of suburban development for at least three decades, he suggested that we should be looking at established urban communities which work - such as Bertie Ahern's home turf of Drumcondra, developed between 1880 and 1920 - to see what lessons we can learn from them.

The area Mr O'Connor chose to focus on is bounded by Drumcondra Road, the Royal Canal, Botanic Road and the River Tolka. It's a Victorian-Edwardian suburb, with extensive mixed housing, shops, schools, churches, pubs and other facilities, mostly laid out on interconnecting streets with very few culs-de-sac.

"Homes range from fine villas to humble artisan houses, giving a natural social mix and mix of age. I doubt if anybody living in the area takes their car to buy a bottle of milk or go for a drink", he said. The area is also well-served by green spaces, including the Botanic Gardens and linear parks along the Tolka and Royal Canal.

"So why aren't we promoting this kind of development - mixed housing, mixed community, pleasant places?", he asked. Was it because people couldn't park two cars in front of their houses in Drumcondra? But, there again, maybe they don't need two cars in Drumcondra because of the availability of public transport.

Mr O'Connor conceded that, "by and large with some exceptions" new houses and housing estates nowadays are attractively designed and well-built. However, compared with Drumcondra, they seem much less enclosed, with no comparable "sense of place" and the landmarks appear more scattered and have less impact.

He put the blame squarely on conventional road design criteria which have, it must be acknowledged, left people living in engineering straitjackets. In this light, the ramps which have sprouted on suburban roads in recent years may be seen as a pathetic post-hoc attempt to deal with defects in the original design.

Why, as Mr O'Connor asked, should roads be designed for travel speeds of up to 40 mph? Or be wide enough to allow two trucks to pass each other? Or have services located under the grass margins rather than under the road? Or kept clear by having all the cars parked within the house plots?

He also queried the notion that houses must be a minimum of 70 feet from each other, back-to-back; that more housing can only be achieved by narrowing the house plot to squeeze more in; that open space can be calculated as a simple percentage and that culs-de-sac are necessarily "safer" because they discourage through-traffic.

Among the consequences of designing for a speed of 40 mph are that houses on corners are pushed back to protect the sight lines of motorists and that no houses may be built fronting on to "distributor roads", so these roads are usually lined with the often-chaotic and unsightly rear boundaries of the houses turned away from them.

As for the requirement that water, electricity, gas and telephone lines must be placed under the grass margins, the Fingal county architect said these services have to cross the roads anyhow, so what's the problem? And just how often do two trucks, or two fire engines, have to pass each other on a residential street?

Open space on suburban housing estates is usually calculated as 10 per cent of the overall site. But Mr O'Connor said it often turned out as SLOAP (Space Left Over After Planning). Spaces neither designed nor overlooked were "wasteful and frequently a nuisance" while co-ordination between adjoining estates was "problematic".

Overall, the "open character" of low-density suburban housing means that the population is spread so thin that communities cannot support small businesses." Add to this the very long delay in school provision and "you have an isolated population which spends a lot of time travelling around in cars . . . even to do the most simple tasks".

Having thus debunked the entire suburban thesis, he suggested an entirely different approach - starting with the idea of designing for speeds of less than 20 mph, or half what it is at present. The best way, according to him, would be to reduce the visibility of motorists by curving the streets and making them narrower.

"Bring houses closer to the street edge, and make people park beside their homes or elsewhere off the street," he said. This would, of course, reduce the length of front gardens - but Mr O'Connor believes that the standard suburban front garden, usually 25 feet long, "is of little use anyway".

He also favours concessions for housing with "designed-in privacy", such as windows orientated not to overlook the neighbours' back gardens, because such schemes would help to reduce back-to-back distances between houses. Meanwhile, services should be put under the roads or footpaths "where they've always been".

His proposal that there should be more loop roads, to "stop this cul-de-sac estate design", is perhaps the most surprising. It rejects the accepted view, promoted by the very influential Essex design guide, that culs-de-sac are safer, insisting that without a reduction in road widths they can be quite dangerous.

As for open space, Mr O'Connor believes that developers should be required to make a contribution in lieu to permit the creation of "quality neighbourhood open space" on higher-density suburban housing estates, with the master planning of green space for many developments being provided by county council experts.

Fingal County Council is to publish its own design guide for residential development in April, initially as a draft to allow for a period of public consultation.

Mr O'Connor put forward the notional case of a 20-acre site and how it might be developed at the standard eight houses per acre or at double that density (16 units per acre). The unit cost, after allowing for a much higher design input, of the latter scheme worked out at £84,000 - saving 10 to 14 per cent.

He said spiralling house prices show that we have more of a land crisis than a housing crisis. The Bacon report had correctly identified the need to increase the supply of serviced land, "but it also said that we must address the low density at which we build so that we can use the land more effectively".

The density issue is also bound up with the whole concept of sustainable development and making the best use of resources. "When we build to a higher density, it also means to a higher quality because developers will have to pay for a real design service. Detailed design is the secret of a good quality residential environment".

Mr O'Connor said it was a question of building coherent, mixed communities "as we did in the past". And though opinion among councillors on the density issue is only slowly changing, they would be aware of the problems with existing standards and he urged them to "keep complaining until you get plain, common-sense answers".

He also stressed that a new community without a school is "no community". The way to overcome continuing delays - often very long - in the provision of schools was to "take away the decision on who gets schools, where and when, from central government", he said. "The school must go in with the first houses".

The Fingal county architect's views on housing density and estate design are shared by his counterparts in South Dublin (Brian Brennan) and Dun Laoghaire-Rathdown (Derek Jago), as well as by the associations representing architects and planners. They are bound to be reflected in new housing design guidelines, due out next Tuesday.