A driving ambition

The A13 is not, at first sight, a thing of poetry. It is busy, not grand enough to be a motorway, grinding its way eastwards from the City to Southend through plains of half-abandoned industry.

It is surrounded by acres of slack space, yet runs painfully close to the fronts of semi-detached houses, whose leaded windows and cottagey pitched roofs proclaim a wish that they were looking on to something more bucolic. The Road to Mandalay it is not, nor yet Route 66, nor even the Westway, whose concrete viaducts have a certain blunt majesty.

The Irish architect Tom de Paor, 35, however, sees it differently. "This is really charming," he says of the views around the Ford factory in Dagenham. As we pass through Barking he rattles off the area's history as if he were a tour guide describing the Tower of London.

Over there is the house where the gunpowder plot was hatched. That is the place from which William the Conqueror ruled the country before he moved into London. That is where one of the greatest medieval fishing fleets was moored. "All roads lead to Barking," de Paor says. "It's the belly button of England."

Over there, beyond B&Q, is Barking Abbey, the country's largest Benedictine nunnery at the time of its dissolution. "That place is full of gangsters," he says, waving towards a blameless-looking estate. Underneath our tyres is the oldest metal flyover in Britain: "It's a very pretty thing." The architect's only disappointment is when looking for a coffee, we pull in to a McDonald's which, despite a big welcoming bag of inflatable chips bouncing about on its roof, is closed. "I thought McDonald's was always open, like churches," de Paor says.

Racial stereotypes are dangerous things, but it's hard not feel that, when discerning the hidden meanings of the A13, it helps to come from the land of James Joyce. Like him, de Paor invests the most humdrum objects with mythic significance. Whether or not it is in his genes, de Paor is now applying this attitude to "the largest public art project in Europe", which he is leading.

The project, called Arterial, will take 10km of the A13 - the stretch that runs through the London Borough of Barking and Dagenham - and make it into "a perpetual rhythmic form whose movements are all of a piece". It is being integrated with functional road improvements already being carried out along the A13.

When the project is completed next year, de Paor hopes that drivers will experience a kind of subtle visual symphony made up of the road, its already existing landmarks and new insertions into the spare pieces of land which, like with any big road, run along its side. The most dramatic of these works will be three wooden towers, each 100ft tall, called the Ethel, Guy and Henry Tudor Rockets, after Ethelburga (a local Saxon saint), Guy Fawkes and Henry VIII. "They will make the Angel of the North look like a toy," de Paor says, modestly.

Between these towers will be sections with strips of hedges in alternating colours, and crash barriers designed to create a shifting moire pattern for passing drivers. There will be what de Paor calls "reptiles", earthworks to shelter the surrounding areas from the road's noise, clad in scaly interlocking tiles. There will also be paths in green, white and gold tarmac: green for bikes, gold for pedestrians and white to divide the two. This is the architect's quietly subversive response to being told to "F*** off, Paddy" by one or two local residents. The colours, of course, are those of the Irish tricolour.

Some of these paths are already there, as is some of his planting and, most conspicuously, something called Holding Pattern. This is a grove of steel posts in the middle of a roundabout, arranged in rows that align with a Roman road, with blue airport landing lights on top. It is hard to say exactly what this field of nocturnal colour achieves, but it gives the roundabout a new sense of occasion - of being more than an accident of engineering.

This is not the first time that local authorities have sought to tame roadbuilding with art, and the beautified motorway is not an art form with a particularly glorious history. Too often it is a matter of hopeful tile patterns or isolated sculptures, which only add to the roadside clutter.

These are the urban equivalents of the little lacy covers people sometimes put on toilet rolls or other objects of blunt function, which serve only to advertise the embarrassing thing they seek to hide.